I'm migrating a 1.5 site to 2.5 using SP Upgrade. All the documents and users went over, however when I upload a 2.5 template the template manager settings are buggy: nothing shows unless I refresh the screen again.
Did you clear cache after upgrade? Can you post some screenshot so we can see what the problem looks like? Make sure that all files and folders have proper permissions set
Attached is an image. A caches appear to be cleared. It was a clean 2.5 install to a new folder in preparation for migrating the data and documents and then moving it to the root.