Trouble with opening EWP Files

Hi everyone,
I am just starting with Grasshopper and Ladybug so please don´t judge me.

I am trying out the tools available in Ladybug at the moment and trying to run the radiation analysis tool I came across the following problem: The EPW file that I am trying to import seems not to be working. I am running the same EPW file to run the sun path tool so the file itself can not be the problem.
But whatever way I try to import the file (open, download, or just the path to the file) i always get an error that the file can not be found. also the file it is looking for is apparently an .mtx file which doesn’t make sense in my opinion. by means of connecting a panel to the epw + stat tool I can see that there is an epw file coming out but as soon as I connect it to the epw file input on the gencumulativ skymtx tool the error appears.
what am I doing wrong?
Thanks in advance!