[exim] Problem with Exim / Spamd

Hi all,

I am facing some strange problems with my exim+spamd setup:
a) an increasing /var/spool/exim/scan directory
b) an increasing /var/spool/exim/input directory

I call it strange because with no apparent reason I can get from 0 to 10GB
of /scan in less the 24hs and from 0 to 80GB in /input.

I am not sure if this is something with my exim / spamd setup itself but I
have another server with the same combo that does not behave like this.
I've tried to ask for cpanel for support but essentially they gave up :(

Someone suggested that it was a hardware problem or insufficient resources
but I am not too convinced about that. Anyway I've tested the memory and
the disks without any error message (or lockup etc).

The /input grows until I delete old messages (for example older than 5 days)
or eats all disk space. With /scan is the same thing altough in a much
slower pace.

Here is my information:

CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 4800+
Mem: 2GB

OS: CentOS release 5.5 (Final)

Error Message:

*2010-07-26 11:14:23 1OdPNk-0002Og-ME spam acl condition: cannot parse spamd
output
*