PERC 6/i Controller - RAID Adapter, Memory Error, Check SDRAM connection

We have a problem with a Dell poweredge 2950. We took out the PERC 6/i RAID controller and after putting it back in the slot we are now getting an error when booting up

RAID Adapter

Memory Error!!!

Please check the SDRAM connection

We have already tried reseating the sideplane and the RAID controller, along with all the cables that plug into it. Any suggestions on how to resolve this?