I've been getting a few emails recently regarding how 0.0.3c doesn't actually work at all. There's a simple reason for that; I broke the core badly at 0.0.3, and of course I haven't been able to fix it. The most stable version of DSemu is probably 0.0.2g, which you can get here:

http://dsemu.org/dsemu-0.0.2g.zip

http://dsemu.oopsilon.com/