Perhaps it has to deal with an interference, since I can’t upload something too. The best solution is to wait until it fully works again. An other possibility might be your browser: try to upload your file with an other browser or clear the cache and the cookies in your current browser. I think it has to deal with an interference, but trying these things won’t hurt (I guess).
Update: It works fully again, it might be a great idea to try again.
Not siting behing a firewall or something els that interferes with your uploads?
Everything works fine, try with FTP i just uploaded 2 GR/projects from Google Chrome
I just uploaded a file too. Works fine to me with Chrome.