Blocks

Hi John,
I just upgraded too and have the same problem. Traced the problem to some third party modules we're using:

1. Turned on debugging: Site admin block > Server > Debugging > switched Debug messages to all and ticked Display debug messages.
2. Switched on editing in a course and checked the debug messages which appeared on screen.
3. Noticed that the Book and Questionnaire modules were mentioned in the error messages.
4. Switched off the Book and Questionnaire: Site admin block > Modules > Activities and closed the "eye" next to the offending modules.
5. Switched off debugging

Not a great fix as we use the questionnaire a bit. But all I can do for now (doing upgrades late at night to avoid disrupting service).
I think it may be a case of waiting for third party modules to be upgraded to work with 1.8.
Maybe there's an easier fix, but reading a couple of other posts, it appears the problem affects several non-core modules.