I would have to disagree that is not nessicarily true; that is why Intel even states it right on the memory specifications page.
Note: This list is not intended be all-inclusive. It is
provided as a convenience to Intel’s general customer base, but Intel
does not make any representations or warranties whatsoever regarding the
quality, reliability, functionality, or compatibility of these memory
Also, since the system has been running without any issue at all since June of 2005 with the original two modules and since November 2008 with all four modules; I really don't think "compatibility" issues would start becoming an issue all the sudden. I have worked with Intel boards for quite a while and although I know they are one of the more "picky" (if you want to call it that) brand of motherboads when it comes to memory; as long as you buy a good brand of memory that adheres to the specifications that Intel sets for the motherboard then there are usually no issues at all.
Anyway, after some hardware testing last night after business hours I believe I found the issue to be an actual bad module of the first pair bought in June 2005. I haven't validated that yet with Memtest because it would have taken more time than I had last night but I hope to this weekend. I believe that the reason that all four of the modules were being labeled as failed during POST was because the module that seems to be bad was in the first slot (DIMM1B); which is the primary slot that needs to be populated first. I believe since this primary module had somewhat failed it was making the system throw the POST errors on the rest of the modules since the first one wasn't being fully detected. As of now the system appears to be working normally on the two newer modules purchased in November 2008. Testing this weeked will confirm I hope.
In any case thanks for the reply.