I assumed this was the right place to ask.
I'm using Windows XP Pro and Leap FTP Program for uploading/downloading files. I've been having some sort of a problem when uploading files into my web server lately. The FTP connection stalls out while uploading a file into _all_ of my web servers that are hosted on different providers.

The error message is:

421 Time Out
No New Data for 900 secs
Error: Connection Aborted.

I've enabled PASV and Anti Idle modes yet stalling out still happens.
What could be the problem ?