I meant that the site's pages could be returning a pagesize of 0 and no content to G. :)
I have a site that is doing that atm, having shifted hosts - normal visits get the code fine, and other sites on the host are fine.
The symptom was the number of pages indexed dropping day by day.
No freaking idea whats happening, but the code is really old so I did a wget of the site, overwrote it with static copies for the interim (which are loading to G fine) and am rewriting the site. It was due anyway; its been a maintainence problem with its crappy old code anyway.
It occurred to me there was a small possibility that had happened to you, although unlikely from your description.
(Please don't derail the thread for my siutation - I have it under control and don't need advice! :))