Error 500 when I try to import a theme demo

Hi, I've buy Catch Vogue Pro Theme, now I need to import a Demo. I've installed and Activated Catch Themes Demo Import plugin. Then, I go to => Dashboard => Appearance => Catch Themes Demo Import => Select the demo you want to import. When I try to import the demo, after a few seconds I obtain: Error 500 The licenze is activated. Someone can help me? Thanks very much.