Pyro 5 sees the wrong disk size.

Hello.
I did a search but could not find this problem.
I've mixed music to be 79 minutes and 59 seconds long. I put in an 80 minute CD and tell Pyro to burn. Pyro tells me that I have a 74 minute CD in the drive. I leave the CD in the tray and save my mix as a .wma file - open Media Player and burn the 79 minute track.
How do I, if is possible, fix this?