For an error free installation we need to make sure that all files that Kappris needs are closed and not in use. This also applies to an upgrade.
Follow this procedure:
Close Word, Outlook, Excel and KPMGR.
Open a command prompt window as administrator.
Run the following commands:
NET STOP SPOOLER
NET START SPOOLER
Now run the installation msi in the same window.
The installation should complete without any messages telling you that files are in use.
If you DO get a message similar to the above the please CANCEL, resolve the issue and start again.
If you are installing on a Terminal Server or similar then some of the processes above may be in use by other users. Check using Task Manager and close if necessary.
I have attached a batch file that runs the DOS commands for simplicity - please run as administrator.