In OBM CONNECT release 2 (10.10.20.91) and OpenBridge Designer (10.10.20.34) there are some missing files that cause the Civil Reports to now work and they open a blank window.
To fix the issue please download the ZIP and extract the contents of the ZIP to "C:\Program Files\Bentley\OpenBridge Modeler CE 10.10.20\OpenBridgeModeler\Default\Reports" for OBM and to "C:\Program Files\Bentley\OpenBridge Designer CE 10.10.20\OpenBridgeModeler\Default\Reports" for OBD.
Open the file again and generate the desired report.