IN server 10, I replace closed files all the time with new copies. (I keep closed back up copies from Server B on Server A and vice versa so that I can host all files from one server in case of emergency) I don't have any problems doing so and in fact use a system script to automate the process.
Check your folder access permissions on the folder where these files are located. It could be that they are not permitting "write" access to your files.
Thanks for the response.
I have full rights.
I ended up having to close all databases, and reboot the server, in order to replace the corrupted database.