Hello everybody 
the following screenshot shows my view of the Data Export Tool:
Initially, I was confused because the CSV files created by the Data Export Tool were somehow broken because the Data Import Tool was not able to import them.
Then I found out, the reason might be all the documentation and additional information which was in the CSV file.
Looking at the Frappe ERPNext Documentation I saw, the ERPNext should actually show me a checkbox rather or not it should include additional documentation in the CSV file and it should show mw filter options.
Both are not there 
What could be the problem here?