Hmm... hello.
Excuse me for asking, but... "I have them in their own folder"? Do you actually have the CHD´s in one folder?
You need to set up a structure similar to this:
> have your "MAME exe" point to a "roms" folder (or "mame roms" if you prefer that)
> each CHD-game needs to have its own subfolder under "roms" (you cannot use a "general folder" for CHD´s...)
> the CHD´s should be placed, uncompressed (not zipped) into their respective folders
For example:
If you want to play "Area 51 - Site 4" this is an example of how your setup structure could look like :
E:\mame (main folder, MAME)
E:\mame\roms (zipped rom "a51site4" is placed here)
E:\mame\roms\area51 (CHD-files "a51site4-2_0" and "a51site4-2_01", are placed here)
Oh, by the way: NO, the CHD´s don´t have to updated unless there are newly dumped files or if the CHD compression "rate" has changed. I think that the current version of CHD´s is "5", so if you got them here on the BDA there´s no reason to worry. They should work.
If, by any chance, the games works better on the 0.268 version rather than the 0.270 version there is not much you can do. Your options are either to have (at least) two installments of MAME OR wait for better/further emulation.
Sometimes a game or two "breaks" when there´s an emulator update available, usually because of newly implemented code (modules etc) or because the main structure of the driver has been changed.
/Happy "retrogaming"...
