The portions of the model that will be compressed during the injection-compression molding process (typically, the part itself, excluding the feed system and cooling system) must be identified in order for the analysis to succeed.
Select the model entities that define the surface and change the property type to Compression surface, then start the analysis again.
To change the property type, right-click on the selected entities and select Change Property Type, then select Compression surface from the list of property types and click OK.