we just bought wp user frontend pro and activated it on our test environment. it does not correspond with our theme (please see http://flux.karrieretipp.net/jobs/testjob1/)
The form itself does not find location (see http://flux.karrieretipp.net/job-aufgeben/), also the upload produces an error.
we therefore wanted to try the plugin with a different theme. Yet, the activation does not work in the other environment. We suppose this is only possible once. Still we need to test. If it does not work with our theme and we cannot test it on others, it is useless for us.
Please help or reimburse the money.
The first link, I don't see anything unexpected (only a PHP error from your theme).
The license is for a single site, so you can activate the plugin in only one site.