itthinx,
The issue was not that it did not upgrade, it did. I even went as far as removing the free version and installing pro and I still had the error showing.
My solution worked fine for me as I had just started using your plugin yesterday and did not have any data besides some general configuration.
Looking in my error log it was likely due to duplicate columns from the upgrade (failing?) not too sure. Either way this issue is resolved for me personally.
-Reece