A 1080 resolution in AIC would be about 3 1/2 hours. Is that about correct? You can open your exported movie in QuickTime and hit command i to see what the codec, resolution, etc is. It would be helpful to post a screen shot of that Inspector info.
It also sounds like Qmaster and Compressor are not getting along on your system. David was probably referring you to Digital Rebellion's Repair Tool, the link to which can be found here. As he indicated, exporting as a Quick Time movie is a better choice than QT Conversion…use the first version to bring into Compressor, where you can test different bit rates until you get the best tradeoff between quality and size.
Russ