Windows Server 2008 Workstation Converter is poorly translated to English, and buggy. Used it twice on two different installs, two different version, both destroyed my 2008 install.
Read the guides all over the net and do it manually man.
I will probably make my own tool soon, because i'm not too impressed with the one that already exists.
No offence if the creator of it reads this! Its still good and I have respect for the hard work done
but it does have problems.
EDIT: That was probably pretty nasty and disrespectful to say all that, sorry
it was only my experience of course - i'm probably just unlucky!