Hello I have exactly the same problem:-
Version mismatch: lesson can't downgrade 2005110200 -> 2005060900
How did you fix it??
This usually means that you somehow have replaced a more recent version of Lesson with an older one. Did you do anything like this?
Version mismatch: assignment can't downgrade 2005060101 -> 2005060100 !
Please post this in the assignment module forum so they can help you out. I know very little about the assignment code
I first installed Moodle 1.6, but this wasn't compatible to the database version of my ISP provider. I deleted all and installed 1.5 and get the message:
A server error that affects your login session was detected. Please login again or restart your browser.
( Continue ) followed by
Version mismatch: assignment can't downgrade 2006080701 -> 2005060101 !
This is very frustrating. Can this issue be solved?
I'm guessing that you did not delete your database. Moodle does not support downgrades. So, I'm afraid you have to delete your database (or clear it out) and then perform a clean install Moodle 1.5.
I've just ran into this error. I solved it to edit the version field of the module that was giving me the error in the table mdl_modules. It might not be clean, but it saved me from having to delete the complete database of this site.