I installed from CDex-win32-1.70-b4-2009.exe selecting Experimental hybrid version 1.70 Beta 4, and all the other defaults.
When the program starts, Options > Settings > Directories & files has C:\Program Files (x86)\CDex\my music\ set for both WAV -> MP3 and Recorded Tracks. I change these to C:\Users\myname\music. (By the way, it's a real pain that the program forces one to tediously navigate to these directories instead of also allowing direct text entry into the boxes.) Then I click OK. The problem is that the program fails to remember these preferences but reverts to the Program Files directory.