I have a problem with downloading in Firefox also. Whenever I download Firefox will permanently freeze and bog down explorer so that nothing responds. I usually have to hard reset when this occurs which is a PITB. I've downloaded Flashgot and synced it up with Free Download Manager, and I also use Download Accelerator Plus in place of Firefox's download manager which fixes the issue, but this is a problem that really bothers me and I hope that it is fixed in future releases.