Reg Exp gives Error 3

Tried to rename 01-14 Mad04-26-2014_22-32-07Count-604959.jpg
to
AX 04-26-14 604959.
I used : Reg Exp
Old Name: Count-(.+)
New Name: AX 04-26-14\1

I get the following Error:
An error occurred renaming 01-14 Mad04-26-2014_22-32-07Count-604959.jp
The system cannot find the path specified. (3)
Bob

I tried this and it worked fine here.

Are there any missing details you can think of?

I should have done a restart before the message, it does work fine. Thanks again Leo. I might mention, after tons of support on RegEx, I was able to complete my first RegEx. I used your help which was easier to follow than I experienced in the past.

Bob