Hi nite_monkey
i've been tracing all you post related to this problem all over the internet. I had the exactly same problem as you do and I solved this probelm.
The key is that you have a wrong version of your termsrv.dll file. I don't know why you replaced your termsrv.dll but if I am correct, the file you have is for Vista while you have Vista SP1 running.
the version of your dll file could be 6.0.6000.xxxx and the correct one should be 6.0.6001.xxxx
so here is the solution: you need a termsrv.dll from a vista sp1 machine, rename the old file you have on your own machine, and copy the sp1 file to your machine.
the location of the dll file is @ %winows%/system32/
I can't upload the file here, so hope you can find one on other website.
I suppose it's helpful to try this keyword for searching the file. "vista sp1 remote desktop multiple user"
good luck!
//Ryan AnChin
