Hello,
Two issues to you verify:
1 - you're not taking care your dataflow. Because you wanna read the property node after you have the image on the indicator.
2 - Connect an error signal to the output and verify if the .exe won't return error.
See the attached picture to a better knowledge of what i'm saying.
I'm not completly sure that the flat sequence it's necessary with the error signal connected. But this way I'm sure that your initial problem will not occur.
Software developer
www.mcm-electronics.com
PORTUGAL