CentOS - Oct 2013 - Login prompt often hangs

Hi all,
I have a strong Dell server running RHEL5.5
every now and then the server hangs (SSH access is frozen) and when
attemping to login the prompt hangs and after a while the message
" can't update CMOS clock from 2 to 47
CIFS VFS No respone for cmd 114 mid 188"
only a reboot causes it to work properly again.
i tried fsck'ing with no luck.

I must say the server does work very hard often, but I was wondering
what could be the problem.


Thanks!
---
Dolev