First thing i would do is to check if the memory are on the THOL.
If yes, then i will make sure that i have the latest bios, bmc and sdr package.
Bios Version 96
BMC Version 64
SDR Package 47
Update it using the DOS Method
Then i will check in the bios >> Advanced >> Memory Configuration >> Memory RAS and Performance Configuration >>
RAS Disabled - Select Memory RAS Configuration
Disabled - FSB High Bandwidth Optimization if you dont have a CPU with FSB 1333Mhz.
Probably, checking in the TPS on Page 26 may help as there.
Let me know how it goes.