Regarding MCP:
Some patches can be very buggy. You can try to disable them all and enable them one by one.
If you still have problems, I would return to 1.30.
In the MCP.history.guide you can see what kind of changes were made in the versions after 1.30.
Edit: Just had a look, and there are a lot of bugfixes and improvements since 1.30.
Regarding MUI:
Fonts and gadgets settings can be changed without a registration key.
If it's not working via the MUI prefs program, try to start the MUI program that you want to change, and see if it has a menu option for MUI settings.
Change your settings there and see if it works that way.