Error Message - user-mapped section

[Golf Tee Warehouse]

For the last 3-4 days I have Actinic Catalog v7 has been thowing up the following error regularly when I switch views or first open Actinic. (See attached image)

An error occurred while copy C:\Program Files\Actinic v7\Sites\Site1\actiniccore.js to C:\Program Files\Actinic v7\Sites\Site1\PreviewHTML\actiniccore.js. The requested operation cannot be performed on a file with a user-mapped section open.

Before the error message appears the computer freezes for 10-15 seconds and is very annoying, has anybody seen this message before (I have searched the forums and cannot find a similar report).
Any ideas where I could start looking for the cause of the problem.

[Duncan Rounding]

It could point to the file opening slowly perhaps due to AV or spyware checking. Try disabling active AV checking etc to see if it goes away.

Is this on Vista?