UNABLE TO ATTACH TO A W2003 SERVER DOMAIN

I HAVE A WINODWS 2003 SERVER DOMAIN, WITH EXCHANSERVER, ISA 2000, ETC. WORKING OK UP TO DATE. I NEEDED TO TAKE AWAY ONE OF THE SERVER AND RE UNITE IT TO THE DOMAIN. THE EASY PART WAS TO DETACH THE COMPUTER, BUT IT IS IMPOSSIBLE TO REUNITE IT. ALWAYS GET AN DOMAIN NAME MISSPELLED. ALSO THE PC IS UNABLE TO BROWSE ITS OWN WORKGROUP. I’VE TRIED THE SAME OPERATIVO WITH OTHER SERVERS IN OUT NETWORK, WORKING FLAWLESS. ANY IDEAS? I’VE ALREADY RUN OUT OF THEM.
THANK YOU ALL