Feb 10 14:42:21 deliver(www@westwood.coventry.sch.uk): Fatal: setgid(1001) failed with euid=303(vmail), gid=303(vmail), egid=303(vmail): Operation not permitted (This binary should probably be called with process group set to 1001 instead of 303(vmail))

Please check uid/gid related settings in dovecot config file: /etc/dovecot/dovecot.conf.
OpenSuSE package 'postfix-mysql' will create system account 'vmail' with uid=303, please check what exactly you have and make sure dovecot use the correct one.

[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1] OperationalError: (1045, "Access denied for user 'vmailadmin'@'localhost' (using password: YES)")

You don't have correct mysql user and password set in iRedAdmin config file settings.ini, please verify them first.

The problem now is when i put the user name (postmaster@} and password in and the next page shows, "internal server error".

sieve log shows;

Feb 10 14:42:21 deliver(www@westwood.coventry.sch.uk): Fatal: setgid(1001) failed with euid=303(vmail), gid=303(vmail), egid=303(vmail): Operation not permitted (This binary should probably be called with process group set to 1001 instead of 303(vmail))
Feb 10 14:42:21 deliver(pmayo@westwood.coventry.sch.uk): Fatal: setgid(1001) failed with euid=303(vmail), gid=303(vmail), egid=303(vmail): Operation not permitted (This binary should probably be called with process group set to 1001 instead of 303(vmail))
Feb 10 14:42:21 deliver(www@westwood.coventry.sch.uk): Fatal: setgid(1001) failed with euid=303(vmail), gid=303(vmail), egid=303(vmail): Operation not permitted (This binary should probably be called with process group set to 1001 instead of 303(vmail))

this is the mail error;

Feb 10 08:13:53 mail roundcube: PHP Error: Unable to connect to managesieve on 127.0.0.1:2000 in /srv/www/roundcubemail-0.4.2/plugins/managesieve/managesieve.php on line 131 (GET /mail/?_task=settings&_action=plugin.managesieve)
Feb 10 08:13:53 mail roundcube: PHP Error: Unable to connect to managesieve on 127.0.0.1:2000 in /srv/www/roundcubemail-0.4.2/plugins/managesieve/managesieve.php on line 131 (GET /mail/?_task=settings&_action=plugin.managesieve)

and this is Apache error;

[Thu Feb 10 14:44:56 2011] [info] [client 127.0.0.1] Connection to child 11 established (server mail.westwood.coventry.sch.uk:443)
[Thu Feb 10 14:44:56 2011] [info] Seeding PRNG with 0 bytes of entropy
[Thu Feb 10 14:44:56 2011] [info] Initial (No.1) HTTPS request received for child 11 (server mail.westwood.coventry.sch.uk:443)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1] Traceback (most recent call last):
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/web.py-0.34-py2.6.egg/web/application.py", line 242, in process
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     return self.handle()
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/web.py-0.34-py2.6.egg/web/application.py", line 233, in handle
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     return self._delegate(fn, self.fvars, args)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/web.py-0.34-py2.6.egg/web/application.py", line 415, in _delegate
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     return handle_class(cls)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/web.py-0.34-py2.6.egg/web/application.py", line 390, in handle_class
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     return tocall(*args)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/srv/www/iredadmin/controllers/mysql/basic.py", line 40, in POST
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     auth_result = auth.auth(username=username, password=password)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/srv/www/iredadmin/libs/mysql/core.py", line 197, in auth
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     limit=1,
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/web.py-0.34-py2.6.egg/web/db.py", line 649, in select
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     return self.query(qout, processed=True)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/web.py-0.34-py2.6.egg/web/db.py", line 610, in query
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     db_cursor = self._db_cursor()
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/web.py-0.34-py2.6.egg/web/db.py", line 541, in _db_cursor
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     return self.ctx.db.cursor()
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/web.py-0.34-py2.6.egg/web/db.py", line 482, in _getctx
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     self._load_context(self._ctx)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/web.py-0.34-py2.6.egg/web/db.py", line 491, in _load_context
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     ctx.db = self._connect_with_pooling(self.keywords)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/web.py-0.34-py2.6.egg/web/db.py", line 538, in _connect_with_pooling
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     return self._pooleddb.connection()
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/DBUtils-1.0-py2.6.egg/DBUtils/PooledDB.py", line 293, in connection
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     con = self.steady_connection()
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/DBUtils-1.0-py2.6.egg/DBUtils/PooledDB.py", line 250, in steady_connection
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     *self._args, **self._kwargs)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/DBUtils-1.0-py2.6.egg/DBUtils/SteadyDB.py", line 128, in connect
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     closeable, *args, **kwargs)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/DBUtils-1.0-py2.6.egg/DBUtils/SteadyDB.py", line 179, in __init__
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     self._store(self._create())
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/local/lib/python2.6/site-packages/DBUtils-1.0-py2.6.egg/DBUtils/SteadyDB.py", line 183, in _create
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     con = self._creator(*self._args, **self._kwargs)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/lib64/python2.6/site-packages/MySQLdb/__init__.py", line 71, in Connect
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     return Connection(*args, **kwargs)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]   File "/usr/lib64/python2.6/site-packages/MySQLdb/connections.py", line 170, in __init__
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]     super(Connection, self).__init__(*args, **kwargs2)
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1] OperationalError: (1045, "Access denied for user 'vmailadmin'@'localhost' (using password: YES)")
[Thu Feb 10 14:44:56 2011] [error] [client 127.0.0.1]
[Thu Feb 10 14:44:56 2011] [info] [client 127.0.0.1] Connection closed to child 11 with standard shutdown (server mail.westwood.coventry.sch.uk:443)

any ideas?