Single-bit failure error rate exceeded - DIMMA

Hi All - I have a Poweredge 6450 that began logging the following error in SA 1.8.

 Attributes Values
 
Status Critical
Device Name BANK_4/DIMM_A
Size 128 MB
Type SDRAM-SYNCHRONOUS
Speed 7 ns
Failures Single bit warning error rate exceeded
Single-bit failure error rate exceeded 
 

It logs this for Banks 1-4, always DIMMA.  We have replaced the motherboard once, the memory riser board twice, replaced a total of 8 of 16 DIMMS.  We have swapped out the DIMMS in BANK 1-4 From A to B yet the error still comes up DIMMA in all banks even though the DIMMS were previously in DIMMB and didn't show any error there.  I'm having difficulty believing that it is a hardware issue (at least not a bad DIMM) and am wondering if this could possibly be a problem with SA.  The server is up and running fine.  Here are the system details:

 BIOS Information 
 Manufacturer  Dell Inc. 
 Version  A10 
 Release Date  11/06/2001 

NOTE: Will be updating the BIOS to A13.  Motherboard replacement downgraded it to A10.  We were getting the same errors on A13 so I doubt they will stop.

 Firmware Information 
 Name  Embedded System Management Controller 
 Version  5.39 

 Firmware Information 
 Name  Power Supply Paralleling Board 
 Version  2.41 

 Firmware Information 
 Name  Primary Backplane 
 Version  1.30 

 Firmware Information 
 Name  Secondary backplane 
 Version  1.30 
Software Profile 
 Operating System 
 Name  Microsoft Windows 2000 Server 
 Version  5.0 Service Pack 3 (Build 2195) 
 System Time  Wed Aug 04 11:38:26 2004 
 System Bootup Time  Sat Jul 24 09:26:00 2004 

 System Management 
 Name  Server Administrator 
 Version  1.8.0 
 Description  Systems Management Software 
 Contains  Instrumentation Service 5.1.0 
   Storage Management Service 3.5.0 
   Update Service 1.9.0 
   Diagnostic Service 3.0.0 
   Sun JRE - OEM Installed Version 1.4.2 
   Secure Port Server 1.0.0 
   Core Service 1.8.0 
   Instrumentation Service Integration Layer 1.8.0 
   Storage Management Service Integration Layer 1.2.0 
   Server Administrator 1.8.0 
   Data Engine 5.1.0 
   OpenManage Tools 1.0.0 
   Remote Access Card Populator 3.20 
   Dell OpenManage 3.8.0 

Any suggestions, thoughts or ideas would be appreciated.  MY DB Admin is getting worried as this is the production DB Server for the company.

Thanks in advance,

Jules