Export to Disc won't create the file even though it appears to

I am using GarageBand '08 on an iMac OS X Version 10.5.8. I want to export a voice recording as an .mp3 to email to someone. It is only 5 minutes long; spoken word. So, I go to SHARE>EXPORT SONG TO DISC>then choose MP3 ENCODER, good quality, with COMPRESS checked, then EXPORT. It seems to do everything fine, no error messages or anything. Problem is no file is created. I can't find the file and I've tried several times making absolutely certain I know where the file is being saved to and it simply is not there. When I search for the file it is no where to be found. So it appears that GarageBand is making the file but it isn't.

What am I doing wrong? Why isn't the file being made?