first of all, i would like to thank William again for his step-by-step guide. i have finally be able to dual boot Vista Ultimate and XP SP2. here is the url to resolve your ntldr problem:
How To: Edit the Windows Vista Boot Menu Options – BCDEDIT.
look for swoopy2's post. make sure you run command prompt as Admin, go to folder boot on your c drive, then follow his commands. after that, use your easybcd application to edit the list again and save the settings. reboot your system, everything should work. good luck to you all and thanks again to William.