[ddouglass]

If there are two folders/copies of Hoster on the computer then it may be getting confused preventing it from opening.
Are you sure there are two copies on the computer? Right click on each desktop icon and go to properties. Look to see if they are pointing to the same location or if they are pointing to different locations. If they point to the same location then you only have one copy with two shortcut icons. If they point to different locations then somehow you have two copies on the computer.
Either way if you are going to re-install then you will need to uninstall one through the Hoster installation file. This should release one install on MTU's server so you can re-install. If there is a second copy somewhere then delete all the files in the two folders where the two copies are located. DO NOT DELETE anything in the folder C:/MTU or folders under it as you will lose any imports or database you have previously done.
After you have acomplished this then restart the computer, Download the 4.22 again and install. I would wait an hour after uninstalling before you re-install to allow the server to process that before you try to re-install.