Saving files gives problem: not enough acces rights (niet voldoende toegangsrechten in dutch)

Dear community, 

When I try to save my files it says I do not have enough acces rights. I am the only user of my license and the files that I try to save are nothing special. Just blank pages with some text (I made this for testing).

Any ideas? It is very annoying, as you can imagine. 

Thanks in advance, Greetings,

Timo