Error: Object reference not set to an instance of an object at Buildsoft.TSection.get_SectionType()

When opening a model, you get the error:

Solution 1

• Close all Diamonds projects.
• Open Task Manager ( CTRL +  ALT +  DEL or right mouse click on the Windows bar). Click on ‘More details’.
• Go to the tabpage ‘Services’.
• Find the service ‘Gateway’ > right mouse button > ‘Stop’.
  Find the service ‘Gateway Server’ > right mouse button > ‘Stop’.
• Find the service ‘Gateway’ > right mouse button > ‘Start’.
  Find the service ‘Gateway Server’ > right mouse button > ‘Start’.
• Close Task Manager.
• Start Diamonds and try again.

Solution 2

• Reset the gateway prefereces.