[Koha] trouble with z3950 search

Hi, I'm using Koha 2.2.9 with Ubuntu (the pre-build vmware image) and I'm having trouble with the z3950 search. I first added the LOC server but whenever I'd search by ISBN (making sure to look for an item I knew was in the catalog), I'd get a 500 Server Error. I then tried adding the Harvard University z3950 server and the Boston Metro Library z3950 server and tried searching by ISBN for items I knew were in their catalogs. This time I wouldn't get a 500 error but would always get "no item found" or whatever the message was. Anything I might be doing wrong? I did make sure to start the z3950 daemon. Thanks