Paul, it sounds like to me that someting isn't lined up just right and it
causing your failures.  I think I sent you some Continental belts before that
are OE belts and these should hold up for at least 20-30k miles if not more.
If the waterpump pulley or alternator pulley aren't lined up properly then
you could be killing your own belts.  The only other thing I can think of is
a bent pulley on something or somehow either your alternator or waterpump is
turning eccentric (off center) and trashing the belts that way.  Check the
bearings in your alternator and water pump by loosening and removing the
belt.  Take your thumb and put it at 9 oclock and your ring finger and put it
at 3 oclock.  Now try rocking the pulley back and forth.  Now try pushing and
pulling on the pulley.  Now do the same thing except move your thumb to 6
oclock and your ring finger to 12 oclock.  If the pump or the alternator
moves more than just a hair or makes a noise while you are doing this then
the bearings are shot.
I have new 2.1l waterpumps (VW) for $50 and rebuilt Bosch alternators for
$150 if you need one.

Hope this helps,
Ken Wilford
Van-Again
John 3:16
http://www.vanagain.com
Office: (856)-765-1583
Fax: (856)-327-2242