Ok, this is due to the fact that old trades were found, but could not be continued because the trade format has changed between 1.01 and 1.03. This gives an error message.

Stop trading and close Zorro. Then look in the "Log" folder for a file named "Z2.trd". This file contained the old Z2 trades in the wrong format. Delete it manually. Then start Zorro and start Z2 again.