APIERR_READ ONLY Error when trying to link ArchiCAD and Grasshopper

[Gareth]

When I try to input any information from Grasshopper to Archicad the link it open and connection is made but I get an APPIER_READ ONLY error on the archicad object and nothing shows up in Archicad. I have tested simple geometries and the same thing happens. I have updated to the latest Rhino, Archicad and Link - any assistance would be greatly appreciated.

System Windows, Rhino 7 and Archicad 26