Scripts not functioning post migration

[mark]

I'm getting errors "cannot access" "file not present" in the app event log.

These point to scripts in the child-domain sysvol / the user logs in from the parent domain controller.

There's a parent/child transitive trust between the two domains

Help anyone?

[mark]

Just noticed the policy SID specified in Group Policy is not the same as the SID in the PC's error log!

What do I have to do to make this right?