No problem ...It may not have been your fault ....
The Medieval characters are coded differently and can be awkward so they are still being worked on.
But if all the others work fine then its nothing wrong with your installation or your PC..
Please Note !
Zombies are hard coded .. They will not follow waypoints ... For now they just stand around moaning ...
Until you get close of course
Hope that helps
The only person ever to get all his work done by "Friday" was Robinson Crusoe..