The LMHOSTS file is a very simple text file. It creates a way for the XP box to use NT's native NetBIOS to quickly identify the domain and the domain controller, therefore it can easily join the domain.

There are only two lines required in this text file, just like in the KB article. Be sure to follow the character count rule between the quotes, and make sure you save the file in C:\WINDOWS\System32\drivers\etc  on the XP box, not the domain controller. Make sure there is no .txt or other file extension.

I'm confident that this will relieve your stress, and take maybe 2 minutes time..

Your LMHOSTS file will look like this.
Given your NT domain controller
Netbios name = DOMAIN1PDC
Domain = DOMAIN1
IP address = 192.168.100.100
Note, use TAB, not spaces between entries

192.168.100.100{tab}   DOMAIN1PDC {tab}  #PRE #DOM:DOMAIN1 {carriage return}
192.168.100.100{tab}   "DOMAIN1        \0x1b"{tab}   #PRE {carriage return}
{carriage return}

Save file as
C:\windows\system32\drivers\etc\lmhosts.
Run this command:
C:\>nbtstat -R

Now, join the domain using the Wizard..