Can you activate the socket debugger and then upload some.
Then, once the upload failed send me the log file.
You can activate the socket debugger in: Preferences-> download-> Advanced.
The log file is located at: /Users/[username]/Library /Application Support/Usenapp/Usenapp.log
You can email the log file (zipped) to: usenapp@xoroxsoft.com
Thank you.