Just a note for other users but today after running 'yum update' on CentOS with Plesk 9 after the update refreshed ClamAV Plesk stopped responding.

I tried:
/etc/init.d/psa restart

And saw that Plesk was failing to start.

Then tailed:
/var/log/sw-cp-server/error_log
2010-04-20 06:10:41: (log.c.75) server started
2010-04-20 06:10:41: (network.c.336) SSL: error:00000000:lib(0):func(0):reason(0)
2010-04-20 15:54:48: (log.c.75) server started
2010-04-20 15:54:48: (network.c.336) SSL: error:00000000:lib(0):func(0):reason(0)
2010-04-20 15:54:48: (log.c.75) server started
2010-04-20 15:54:48: (network.c.336) SSL: error:00000000:lib(0):func(0):reason(0)
2010-04-20 15:56:08: (log.c.75) server started
2010-04-20 15:56:08: (network.c.336) SSL: error:00000000:lib(0):func(0):reason(0)
2010-04-20 15:56:08: (log.c.75) server started
2010-04-20 15:56:08: (network.c.336) SSL: error:00000000:lib(0):func(0):reason(0)

And then finally found a fix from Parallels:
http://kb.parallels.com/8338

Just thought there was a good chance your other users might run into this problem and appreciate this post.

just for your info. it's not due to the clamav update.
it's about some centos ssl updates and an incompatibilty of plesk that was discussed here:
http://www.atomicorp.com/forums/viewtopic.php?f=18&t=4007

Hello,

you can find the fix here http://kb.parallels.com/en/8338 .

Regards,