Hello Patrick,
I tried installing your simulator for BlueROV2. The whole process took me a while because I'm new to ROS.
When everything was installed and running I tried to access the BlueROV nodes via the following command:
roslaunch bluerov_ros_playground bluerov2_node.launch
Unfortunately, I got the following error:

I google it and tried a few things but I cannot make it work. I would appreciate your help.
Thanks in advance!