Usb Enclosure unable to copy onto harddrive

I have a 30GB laptop hard drive enclosure. It has windows XP installed
on it but i am running the xp off my home comp.

enclosu retrieving files
not-enclosu running xp and getting files off of enclosure

I get the error, "Cannot create or replace [username]: Access is
denied."

"Make sure the sidk is not full or write-protected"
"Make sure the disk is not full or write protected and that the file is
not currently in use."

I need to get all the files off this HDD. How do I do it?

Thanks