Czech Television made some changes, after which a file with the text "we are sorry, but your version of the application is no longer supported. We recommend updating.

Old and discussed theme, some threads here:

https://wordrider.net/forum/10/20956/ceska_televize_-_ivisilani_p__estal_fungovat
https://wordrider.net/forum/10/21417/problem_czech_tv_-_download

... problem is too hard to solve and probably will not be solved here. My recommend is try another application for download videos from Czech Television.