Error message when trying to open a usual SDLXLIFF file

Hello,

So far I have used the free 30 days trial version and never had any problems. Now, I have purchased the Starter Version and cannot open a simple SDLXLIFF  file. When I click on "translate a single document" and want to open the file the following error message appears (in German, so this is my own translation into English)

 

This project cannot be opened in the Studio version you are using. This project uses a translation source that is not supported in the Studio version you are using.

 

Is it possible that I cannot open a simple SDLXLIFF file (522 KB) with the Starter version? Unfortunately, the live chat was not very helpful. Can you please help me? It is kind of urgent ... :/

 

Thank you so much in advance!!!