[TYPO3-templavoila] Upgrading TV produces TO unserialized error

[Tony Lush]

I have created a clone of an existing web site to upgrade TYPO3 from 
4.2.12. When I go to 4.3.8, go through the update wizard, and update the 
extensions I get an error from TV:

Template Object could not be unserialized successfully.

This happens whenever TV is taken beyond 1.3.7. The original site is all 
UTF-8 and is in three languages.

I have tried opening and re-saving all the TO's. And have tried 
upgrading TV to the 1.4.x series.

How can I proceed from here? We will be taking TYPO3 to 4.5.x before 
we're done.

Thank you -- Tony