seriously, any time your programs are crashing and files start becoming corrupt is a good time to run a quick RAM check.
the havoc bad RAM can cause is unbelievable. corrupting your save files and making them unopenable is just the tip of the iceberg. imagine DVDs you burn, files you save, programs you open, etc becoming corrupt and you only find out about them weeks from now. its just as bad as a hard disk failure.

dont just bookmark it, burn it to a CD and check your RAM every few months on your machines, it takes like 5 min to run a full scan.

its not guaranteed that it is bad RAM, but this type of thing is one of the symptoms. dont put it off, you may regret it.