Can you perhaps do following to create a debug log for us, so we can see where the problem is?:
1. Create a empty text file on your desktop and call it TweetMyPCdebug.txt.
2. Open TweetMyPC and enter your login data
3. Now click at the Save&Hide button in TweetMyPC
4. close the error message and wait some time.
5. Now open the TweetMyPCdebug file at your desktop and copy+paste the debug log from there and post it here as a comment.
(If the file is empty, check if naming it just "TweetMyPCdebug" without the .txt and then redoing the steps helps)
With this help we should be able to identify+solve the problem fast.
also, in what country do you live? what firewall do you use? Any proxy servers set up?