Oh, that sounds wierd :P i've never had problem with flashget and NOD32, i will search and see if i can find another program that might help you.
here is a page where you can find alternative programs that can help you with your download speed:
I have never tried any of them, so i have no idea how those work.
But i would still recomend getting flashget, just add it to ignore on NOD32. Or wait for some other solution that the mods here might have.