I use an R4 and no problems here. Make sure you are patching a clean ROM. Also, make sure you save file is the same name as the patched ROM. (without the .nds part)
When using v3 patch, I keep getting some error that says file can't be copied or found.
Is it patched or what? How annoying.
EDIT: Thanks for the tutorial vid!
I too have experienced the freezing, but after the patch, nothing so far. (knock on wood)
I heard it was anti-piracy blocks built in the game which causes the freezing.