Hey there papeter and welcome to the forum.
When you compacted the folders/files it should have created a .DBX file on your drive, this should contain all the emails it compacted.
You should be able to use a program called DBXtract to recover these emails, you can download it from here:
http://www.pcworld.com/downloads/fil...d,23383,00.asp
The next link explains how you can use the program, it may be useful:
http://www.updatexp.com/tip23.html