Arlen would be the best person to answer, but while we're waiting I'll ask some questions.
How do you normally launch tiddlyserver? An upgrade to ts shouldn't affect your personal
files unless you did some unusual like putting them into the node_modules directory.
So if you can remember how you launch, then you should be able to find the configuration
that will tell you (or remind you) where your personal files are. With TS, your personal files
could be anywhere on the system, depending on configuration. So your personal files should
be there -- you just have to remember where.
Looking at the logs, it appears that ts didn't have enough permissions to complete it's process.
Possibly if you opened an administrator box and ran the upgrade it would complete. Perhaps
that is what you did when you first installed and have forgotten. But, like I said, you might
want to wait for other input.
Good luck!