I think Microsoft's FolderShare is a very useful program for synchronizing programs across multiples computers (also makes a quick-and-easy backup solution). When I got my new MacBook Pro I was excited to see that they have a Mac version, as well as a Windows version, so that I could retain the same files, and backups, whether I'm working in Mac or Windows.
But I spent hours finding a way to make the files transfer from Windows to Mac (the other way around, Mac to Windows, worked fine from the get-go). Hours of toying with proxies, and my router, were a waste of time.
The solution (for me): Disable Encryption. In the Settings -> Transfers tab, when I turn off "Encrypt transfers" it works OK. When I leave it off, it fails.
It's working great for me now. My file bits are flying around the Internet unencrypted now, so please, everyone, don't peek. If anyone has a way to make FolderShare work between Mac and Windows with encryption, please let me know.