First of all, you don't need the zipped emulators on there.
Right, I'd say your problem is just one of menu navigation... Have you actually booted up the emulators? On the GP2X menu, after you select Games and then the SD card, you then have to navigate to where you unzipped the emulator and select the .gpe file (e.g. squidgesnes.gpe).
Once the emulator starts, do whatever it says in the readme.txt to tell it where you put the roms.
For SNES, you may have to select/deselect "Use absolute ROM paths" in the option menu to be able to choose your own rom directory (otherwise it will look in <your SD structure>/squidgesnes/roms/).
For DrMD, the menu will allow you to navigate to wherever your roms are stored, then there is an option to save that information so you don't need to re-do it every time.
Good luck!