I had a similar problem when I tried exporting a full rez version of my film. Is the hard drive that you are saving to formatted FAT32? If so, this is the reason. FAT32 formatted drives can not save a single file larger than 2 gigs.
I am just using my mini-dv camcorder as a deck (Sony TRV-17). There is a setting on the camera to switch A/V in or out. Just got a second monitor and DVI to ADC converter to make it all work. So nice to have all that workspace.