Thanks. With my Verbatim 80 minute CD-R, it shows me 359,844 seconds free, or 79:59:69. When I created an audio file exactly that long, Imgburn said it was too long and offered me the choice of truncating it, or overburning. Maybe, as you suggested, the error message is erroneous because it might not take into account that the pregap starts at frame -150 (-2 seconds).
Anyway, I made an audio file of length 79:57:69, and it recorded without complaints.
This is a little academic because my audio file is the most boring one possible, unless you are an avant garde composer. It's all silence. I'm using it in conjunction with a board that taps into the cd player signal line in an older car stereo to provide an aux in jack for mp3 players. Just for fun, though, I might try burning the 79:59:69 wav file (that does not shave off 2 seconds for the initial gap) to see if it will actually record it.