This page should provide infos about known problems when upgrading a version.
Due to a change, the 'test' scripts of the Tryton-Server have moved. When accessing the 'Modules' Section via the GUI, the a.m. error message appears.
Solution: Delete the entry from the database. Open a shell on the server (assuming you run a Linux-machine):
sudo su postgres
psql
\c your_database_name
delete from ir_module_module where name = 'test';
\q