Everything was working fine, but with no changes to my templates, my rebuilds started timing out. Today I got an email that the ads were no longer there, and sure enough, they were gone on the main pages that had been partially rebuilt. I removed the ad network code from the templates, and the rebuild goes fine. I cleared the ad_network txt file, and it still doesn't rebuild. Do I need to raise the timeout values or something? Thanks!
OK I fixed this. My host must have changed something in how .php works. I monkeyed around with it, and ended up getting it to work by changing the "www" to "localhost" in the url of the include I add into the pages. Not sure why I needed this change, but it fixed the problem, and the rebuilds work now with the ads coming up. Just posting for refererence in case someone else runs into similar problem.