Adam,
I told you that the server is the same server where the version 5.0 is running without any problem. I just did the same I did when my boss asked me to install the version 5.0 for the first time, copy the files.... nothing else!
If any other different version of MSXMLDOM must be installed you should specify when releasing new versions which are the requirements cuteeditor version 5.1 needs and I'll have a look and I will ask to install in those libraries or whatever which our server wouldn't has installed.
David