Yes, I am running 2.0.10.
I just updated the system module at the suggestion and now the main menu and login block content have dissappeared as well!
I now have all headers, with no content. The headline content remains though...
Next idea? Maybe that points something out?

Hi.
I have the exact same problem on www.meckyr.com. I'm rebuilding this site after a server crash and haven't proceeded to do much because this is bugging me and I don't want to do too much work if I've got to scratch the whole thing anyway.
There are two custom blocks on the main page. They preview just fine, and their titles appear, but the content doesn't appear after submitting it.
How can you determine which system file may be corrupted?
Thanks for any help.