Error message 500(4)

I'm running a CRM package (based on SugarCRM) on my linode.

During a database file import I get an error message "500(4)".

Not sure if that is a linode error or distro error or application error?

Running ubuntu 10.04 lts. Running linode 512.

During the file loading the CPU usage is 100% or higher for 5 minutes or so, then I get the error message. When I check the imported records its completed about 3000 out of 6000 records.

If I break the file into a smaller chunk of say 2000 records it imports ok no error message.

IO and Swap IO utilization are both very low.

Thanks for any help/suggestions.

Adrian