Thats true, thank you for your effort!
I found out that the problem is that the appeared height (block with the transaction in it), cannot be read from the transaction details. If i set it manually to some random blockheight the wallet starts at least. So i guess its some issue with the protobuffer language that decode the raw data, which i am nor very familiar with. Anyhow at least i can send transactions now. The problem here was that i calculated the demurrage too late during transaction generation.
Rik