When I get this error it's usually because I've opened the file in Excel/NotePad/PickYourEditor that has a lock on the file.
How are the files being created? Is the create process running too?
Jack Corbett
Consultant - Straight Path Solutions
Check out these links on how to get faster and more accurate answers:
Forum Etiquette: How to post data/code on a forum to get the best help
Need an Answer? Actually, No ... You Need a Question