Some time there will prompt below error..do anyone have any idea?   

(!!)WARN: all primary virus scanners failed, considering backups: 2 Time(s)
    (!)ClamAV-clamscan av-scanner FAILED: /usr/bin/clamscan unexpected exit 2, output="WARNING: Ignoring deprecated option --disable-summary\nERROR: Option --tempdir requires a non-empty string argument\nERROR: Can't parse command line options" at (eval 92) line 594.: 2 Time(s)
    (!)ClamAV-clamd av-scanner FAILED: run_av error: ask_daemon_internal: Exceeded allowed time at (eval 92) line 372.\n: 2 Time(s)
    (!)run_av (ClamAV-clamscan) FAILED - unexpected exit 2, output="WARNING: Ignoring deprecated option --disable-summary\nERROR: Option --tempdir requires a non-empty string argument\nERROR: Can't parse command line options": 2 Time(s)
    (!)ClamAV-clamd: timed out, retrying (2): 2 Time(s)
    (!!)TROUBLE in check_mail: virus_scan FAILED: AV: ALL VIRUS SCANNERS FAILED: 2 Time(s)
    (!)PRESERVING EVIDENCE in /var/amavis/tmp/amavis-20100422T102747-25378: 1 Time(s)
    (!)PRESERVING EVIDENCE in /var/amavis/tmp/amavis-20100422T102339-25283: 1 Time(s)