Firstly: I see that you speak German... as general practice, people do their best to speak English here. We can translate with Google Translate (as I have done), but this would be tedious if we had to do it for every person. We are quite welcoming to non-English speakers, even if their English is poor at best.
Secondly: "Help" (or "Hilfe" in German) is a very common type of problem... almost everyone here asks for help. Try to make your subject line more descriptive.
Thirdly: You show a screenshot of your code and your error... a better way to do this is to paste your code and to paste your error. This way, we can try to duplicate it in full (or at least see all of your code to try to spot errors).
For a first post, this is no problem, but just some points for the future.
Now, to figure out the source of your error...
(Translated to English)
Hello
can anyone help me
?
It
ran all the time
and
now
comes this error message
...
I'm totally
new to the area
...
The error is that you are trying to access an element of filename that doesn't exist (specifically element 1, or the second element). If you didn't change the code, then perhaps, did you change the files that the program has access to?