PowerEdge R410 memory error on post

I called in about this issue and have service request #  940194349 but couldnt get suport since its out of warranty?

this is this issue:  I have Dell PowerEdge R410 server.   I added two 8GB memory modules to the server and on post I get this error:

Memory Initialization Warning: Memory Size

MEMBIST failure - The following DIMM has been disabled by BIOS: DIMM A2

Unsupported memory configuration,  DIMM mismatch across slots detected.

The following DIMMs should match in geometry: DIMM A1, A2 & A3

The server sees 32GB but only 24 usable.  currently there is an 8GB DIMM in slots DIMM_A1, A2, A3, A4

Mike