Hello,
I had this same problem a while back, and it happened again.
What I did was that I made a small edit to the website (I added some html 'title' tags to some images) and then modx went bonkers. The content outputs "too many forward attempts" and the manager looks like this:
http://i41.tinypic.com/o5vsw8.jpg. The first time I thought it was because I was using an old version of modx (1.0.0), but I reinstalled it using 1.0.5, and it worked just fine. I currently have a non-modx backup of the site running, and if I can't figure it out, i'm going to try re-installing it again. Still, this is really annoying.
Cheers
Marco M