Everytime i download any big file thats over 700mb (like sro) it stops at 99% and fails...and i have no freakin idea wats the cause of that

and it pisses the hell out of me especially because i have a 256K DSL and it takes like 12 hours to download a big file.
Anyone knows this problem or knows a solution to it?is it an ISP problem?
..Thanks in advance.