For questions and problems with the CMS core. This board is NOT for any 3rd party modules, addons, PHP scripts or anything NOT distributed with the CMS made simple package itself.
I just discovered the exact same problem today. I was getting errors when trying to view index.php or any other page. Logged into CMS MS and had funny bits of code showing up in the CMS menus. I've made absolutely no changes since it was last working.
Now it appears the entire site is down! I think MT must be having some problems. I've submitted a support ticket about this to see if they can tell me if they changed anything which might have caused the errors. Finger's crossed--I'm the sure the client it not too happy!