Whenever i try to play a DS rom it always comes up with "Unable to access save data. Turn the Power off and reinsert the game card." or the like I tried clicking the "Save options" button and it told me "setup saved", but it still won't work. any advice?

Depending on what game you're playing, you have to set a compatible save type in No$Gba's settings.

How do you do that? I can't see any useful looking options, and the site doesn't say anything, thanks

Options --> Emulation Setup --> NDS Cartridge Backup Media.

The program isn't very complicated. Experiment a little.

Having said that, I've experimented will all available settings and still can't get a certain game to work...

Ah, many things can be done, with a lil tinkering.
It's the first 3 options i think.

Great thank you:D