Yes this sounds like the old issue of windows being daft and not allowing patches to apply.
Try this....
COpy the entire directory OR reinstall OUT of programs folder. Since i fist encountered this issue I have always installed direct under C or my E drives. OUT of programs folder. Since this never an issue again. Still do not understand why this happens, but seems to be totally a windows 64 bit issue? I can not remember if I had problems with K43 and my old 32bit vista laptop. I dont think I did.
K43 is a solid game. If it takes to you give APOS a try.
Its K43 on crack better. And k43 is good. How many late nights with k43 fighting half tracks =)
Oh i am 1 month late. =(