Uploads stalling?

I'm having trouble uploading anything to my FTP server, or any other FTP servers, for that matter, including my iDisk.

The file apparently starts uploading, but stops pretty quickly, and just hangs there.

I've plugged my computer straight into my DSL modem, and it functions fine- it's just when I try to upload anything via my wireless connection, it chokes, and on multiple computers. Any ideas?