Hi,
I managed to upgrade 2.5 to 2.7, on the way to 3.1.
During the 3.1 upgrade, I get mysterious errors when I reach "Plugins check". Several plugins can't be "found" in the directory tree. For example, the error above says that 'qtype_match' not only fails, but is unavailable. That file is in my /questions/type/ directory. Similar failure to find other plugins happens with other plugins.
Clicking "Upload Zip Files" just returns me to the beginning of the upgrade process.
What's the solution? (Everything is backed up so I can restore to the original I had this morning. But I'd rather get these things upgraded.