Your error reads like the issue is specific to the Date value you're trying to pass.  This was in part why I suggested you change it from a Date type variable to String.  You haven't offered up why you're feeding the Flow '1900-01-01' and your error is coming back with '01.01.1900' as the value.  

I did a Google search for it and found a few things:
https://www.servicenow.com/community/developer-forum/glidedate-converstion/m-p/1686084

https://www.servicenow.com/community/developer-forum/java-text-parseexception/m-p/1931221

 

You may need to manipulate your value at the end of line 7 before trying to use it.

Can you provide screen shots from a test execution?  You've given us what you're doing, but only a part of the result.