Sorry I didn't reply sooner, but I had something hosed on my site's phpdig.
I tried just now indexing a few pages from your site, then stopped the spider, unlocked the site, then updated on your site. No problems.
I'm not sure what's happening, but what I'd suggest is emptying all your phpdig tables and spidering fresh. That has seemed to get quite a few people out of a pickle (including me!). You probably won't have to do that every time you spider you site, only this once.
Let us know if that helps.