I sometimes come across the problem where compacting and repairing a database
will actually corrupt my database, or invalidate the links to my tables.  
Mostly I think this is due to the complexity of the front-end I am working
on, or the number of different databases I'm linked to, or just whatever else.

Anyway, make sure you're making a backup copy of your database before you
try to compact and repair.  You said yours is crashing when you try doing
that, so test it on a simple database to see if it'll work on something
small.  If that doesn't work, try converting to an older version of Access
first (Acces 2000 or in an extreme circumstance, Access 97).  Failing that,
try compacting on a different machine.  If it's still crashing, then it's
probably an Access problem, and you'll want to re-install Office on your
machine.  If it's not working by that point, I would personally re-install
the OS (because it might be a library or extension problem), but that's just
me.  I'm odd like that.  :-p

hth,

Nick