I downloaded a new one and kinda blowed into the holes of my NDS and R4 in case of a bad connection or anything. It seems to be working fine so far. Thanks everyone for the replies =]
Just because you have downloaded another rom from another source, it doesn't mean your rom is 100% verified.
To check that your DS roms are 100% which will rule out if its the rom if something goes wrong is to use two things.
Use a rom verification tool such as clrMAMEpro and then use that with ADVANsCEne's latest DAT file.
Once you have checked all your roms, and they are verified then you can start asking questions or checking other possibilities why your game isn't working or freezing.
Although freezing may indicate that its your microSD card in the sense that's its far too slow. Buy a SanDisk ULTRA II 1Gb or 2Gb. According to reports, those cards are easy to get hold of and don't suffer from speed issues.