Audio import issue

When I attempt to import an audio file, GarageBand briefly flashes a dialogue box / progress bar that reads 'Importing File(s)'; the box disappears and nothing is imported. I do not receive an error message.

I have tried, in combination...

• Converting files to other formats (including AIFF 44.100 kHz, 16-bit) both with iTunes and by burning the files to CD
• Selecting the files for import from iTunes and from the Finder
• Reinstalling GarageBand

I am able to play files in iTunes and even to preview them through the Media Browser in GargageBand. The files are not rights protected.

Thanks in advance for any help / suggestions!