If you have phpMyAdmin, go to the Operations tab and look for Table maintenance.
This is an odd sort of error message to get getting. As I said, it's normally something I'd expect to see after coding something incorrectly.
If the sql table is ok, I'd try uploading another good copy of that file. Failing that, perhaps as Ruben says, your hosts have been changing things.
Using version :: 7.5.7 ...sans
SFS at the mo'