Nadya,
Can you diff your class VFP 8 and 9 VCX, VCT library files and see if the output shows anything noticeably different? I know these are binary files, per se, but I often use NotePad to look at these type of files (SCX, SCT, FRX, FRT) when something flakey is happening.
Also, what happens if you PACK these class libraries? (Apologies if you've already done this - I haven't read the entire thread).
Malcolm
PS: Great detective work :)