Single Sign On and Domain Access with Table Prefix on url_alias

Hello, I am having lots of trouble getting my site set up. I have example1.com, example2.com, example3.com, and example4.com plus some sub.example1.com sites. I created duplicate url_alias tables for all of the sites so that each site could have a example.com/home page for the front page. Then I tried installing Single Sign On with disastrous results. I very often get a Page Not Found error with a URL like this:
http://www.example1.com/singlesignon/initial_check?slave_session=87d1591...

Any ideas what I'm doing wrong? Is the problem caused by the url_alias tables?