now.isAfter rule

[ljsquare (Laurens Jan Merkx)]

@mhilbush

DateTimeType is not compatible with now.isAfter, so you need to convert it as described here

This is also a very good explaination: DateTime Conversion

@danst

if (now.isAfter(Min_Rolladen_Open_Zeit)) {

A quick solution:
if (now.isAfter(new DateTime(Min_Rolladen_Open_Zeit.state.toString) )) {