Last time (some weeks ago) due to a power failure my OS went screwed up.
I reinstalled OS in "repair" mode forgetting to log as "Administrator" in final stage and then... several settings and stuff was not set normally.
As result of this stunt, version of UT which I used with XC_Engine 21 doesn't look very friendly, it works sometimes as Admin and fails as "User". I really have to solve it somehow... or an OS DLL file has been "rebuilt" which now is not the right file... Anyway... XC24 with its specific install works normally... but I feel system different compared to what it was. Some day I will need to reinstall everything in a clean state and rebuilding accounts normally...
Resuming topic. I'll move defenses a bit and updating their paths...
As for your case, I would install a clean UT copy elsewhere (not on OS partition) for probing if something was not damaged by whatever "update".
Edit: Here is map with Defenses moved and Paths updated, also here SpawnPoints won't have any useless pathing data - removed using last technology.
See this...