I had 1.4.4 beta installed and it worked, but I had it check for updates, and it downgraded me to 1.3.4
Make sure that the right version is installed. Also, make sure that your ringtones are in the same folder as when you created them. If they have been moved, the program can still preview them, but will not upload them.
Try this if everything else it ok, but you're still having problems.
Browse to where the ringtone is, like you were making a new one, and just go through the steps. It should "create" the ringtone again and upload to your phone.