It's cool.

Well I don't have too much experience with MAME32 since I usually use standard MAME, but MAME32 is based on MAME.
If they work in an older version of MAME and not properly in a new one, that means you may have older versions of the ROMS. A particular version of MAME looks for a particular version of a ROM when it tries to execute. There may be several working versions out there, but they'll be working for specific MAME versions. This is not the case with all games, but certainly a significant amount.
You can either choose to use the older version of MAME (no harm there) or you can find a newer version of the ROM. If that doesn't fix it, then that obviously wasn't the problem. :-)
What specific games are you having trouble with? How many different games did you try?