When exporting the audio from your project its very important that you do it the right way, otherwise it might fail to load into Pro Tools for sound editing, or data might be lost in the transfer. The best way of getting all you audio to us is to make an AAF export.
These are the default setting you should use when exporting an AAF from your timeline in Premiere Pro:

Make sure the correct timeline is selected
Choose File > Export > AAF

Save the AAF file on a local hard drive, and please be aware that all the audio files is stored in a sub folder called AAF Media. We will need both the AAF and the folder with the sound files sendt to us.

The following things will corrupt the AAF file!

Premiere Pro does NOT give you an error if any of the following are present in the timeline. It just exports a corrupt AAF.

Special characters, like /, >, <, ®, and ü, Ø, Æ, Å.
Using Merged Clips in the timeline.
Nested sequences. Sometimes they work, most time they don’t!
If a clip has a transition at both the In and Out points, the clip must be at least the same length as both transitions combined.

Also be aware that choosing to embed the audio files in the actual AAF will strip meta data from the sound files! This wont break the AAF, but it is really annoying as the data helps us to identify the scene, take and the sources recorded.

Fix it when it isn’t working

Sometimes the AAF file just dosen’t work even though alle the guidelines have been followed. Then the best fix is to simplify your timeline! The most bulletproof way is this:

Locate your timeline in the bin > Right click > Dublicate
Rename to (Projectname)_AAFcleanup
In the new timeline remove all video tracks, remember to unlink from audio files first! This should leave you with a sequence only with the audio tracks you want to export.
Go over the audio clips in your sequence and look for unsupported characters like Æ,Ø, Å and rename the files in your sequence (not in the bin). If the names are not displayed on the audio clips in the sequence click the Wrench (Timeline Display Settings) > Show Audio Names.
Export the cleaned timeline as a Final Cut XML sequence
File > Export > Final Cut Pro XML
Import the Final Cut Pro XML file you just created back into the Premiere Pro Project. This gives you a simplified sequence, without Nested Clips or Merged Clips, if they were present.
Rename this sequence (Projectname)_AAFfixed, and follow the normal AAF export procedure as described above.