I would highly recommend that you you work toward upgrading. Until then...
Have you tried to execute the the logon script from a DOS window on XP?
code:
\\server\netlogon\kixtart.exe \\server\netlogon\edc.skr
Does this execute?
NT,W2K, and XP do not use z:\ when executing the logon script.
Do your XP computers display the black DOS window at all when the script should execute?
