You can't open apps created by other user unless you have licensed version.
You need a Named User license to open up a models created by others in the desktop client. Or you have to upload it to your QlikView server and use a document license.
If you have a named user CAL then you can license your desktop client by going to file -> open in server
Open any document on the server and you should have your license.
Without a license there is no way to open other peoples models. This is by design.
check the below link Personal edition FAQ's