WhyMe said:
Is the same issue replicated when you test your second module in slot #1 and then slot #2? If so, then unfortunately you may have a motherboard issue.

In post #14, I wrote Did you check which bios revision you are currently using? If it was an old version, have you tried updating to the newer revisions for enhanced RAM compatibility? It may be worth checking out.
My BIOS version is V26.11. The same stick passed in the second slot too.