Hi,
I have been developing in Qt for quite a few years, and am one of the core developers of a Qt based telnet client, Mudlet (Which you can look at here: [login to view URL] or [login to view URL]). I also develop on a Window 7 x64 system, so I have gone through the exact pain and suffering you are. Though every case is unique, I'm sure I can figure out what is tripping you up.
If you have any more questions, please don't hesitate to ask. I look forward to helping you out!
Thank you,
Chris Mitchell