To troubleshoot I would:
1. Check to make sure I have that homebrew/hack in my games folder on my MMC.
2. Check to make sure the name of that homebrew matches what is in the menu.txt file exactly (to make sure single click on the file name and copy it then paste it into your menu entry)
3. right click on the rom and click properties to see what size the file is.
4. Make sure the rom type has the same file size in it.
5. If it still has the correct file size in it and still doesn't work I'd find another entry in the menu file that had the same file size but other different letters. (say for example instead of HSC_32K I'd change it to 7800_32K).
6. Make sure I have the correct bios for the rom type. if it's 7800_32K I'd make sure it was using the 78BIOS. If the rom type is HSC_32K then I'd have to make sure the BIOS is HSC.....etc.
Lastly, make sure you tab between entries on a menu line or you'll get errors when creating the .CC2 menu file.
edit:
One more thing. If a game is a hack of some other game it's most likely going to use the same rom type and bios as the game it was hacked from. I'd say the exception to this rule would probably be Pacman Collection as I assume it's a larger file size than the original but I'd have to check.