I have no clue, but here are some pointers in directions you might look at (Cover Bugs)
 * 36336
 * 67610

Questions:

• When you remove the cover_db directory, and run it, does it still crash? (how big is that dir anyway?)
• Did it work before and it stopped working or are you setting it up?
• How about running it in chunks (if you have multiple pm's, do you have separate test files, or just one big one?)
• How about alter default values, and requesting less information?