I've been trying to export my finished song for the last 30 minutes. I've searched all the forums and I can't find anything. 
The problem is that when I try to export the tracks (five audio), the "Audio" option is grayed out. I can't select it. I also can't select "Video", "Groove Clip" or "OMF". 
It is imperative that this gets done tonight, and I would really appreciate it if someone could help me out.
All of the files in the tracks are .wav, except one that's .mp3, if that's important at all.

A selection of audio tracks must be made prior to export.

Could you explain further? 

If you're referring to the fact that I would have to select all the tracks before I exported, I have already tried that. It didn't work.

Just to be sure, you've done the following:
- With the track view selected, you've selected all audio tracks, so you see all 5 track numbers highlighted.
- You then clicked file -> export audio and that's where you get the issue?
 
Russ