Strange thing happening on a WIndows 2003 AD, i have an OU and in this OU i have user objects imported from another domain. The problem is only Domain Admin accounts have access to the objects in the OU despite me assigning full control access to other groups. Effective permissions for these groups look ok but when i select a child object the permissions have not filtered down from the parent OU, despite inherit permissions from parent option being ticked on the object.

Any ideas? Driving me nuts!!

When you applied the permissions did you set it for this object "and all child objects" (had to ask,sorry).  Is the "apply to objects only in this container within advanced ticked for your permissions?

Maybe, if only Domain Admins have permissions then AD doesn't have the ability to change them.  Can you add SYSTEM with full control?

Maybe use adsiedit.msc as well to check and/or add permissions? 

Also try clicking the "default" button for permissions?

Finally who is down in the "owner" tab?

Permissions are set for this object and all child objects, the inherit from the parent permission entries that apply to child objects.Include these with entries explicitly defined here option is ticked. SYSTEM has full control. The Owner is Domain Admins. Tried DEFAULT button with no joy.

Can see the objects but just can't modify them. Very bizarre. Not sure how to use Adsiedit so might read up on that. Also swithered if the Delegate Control wizard might work?

DOH!!! I am soooo embarrassed and ashamed to say that i have discovered why it wasn't working.........the drop down box for the permissions was not set to this object and child objects!, it was only set to this object only. I thought it was, on the word of another admin who set it up. I should have checked this and it's the first thing you suggested Andy.

Gonna put it down to a particularly bad day and i must apologise for wasting your time Andy.