It looks like that the geometry is not valid. The postgis layer could be loaded into PostGIS by third party tool which is not complied with the ArcGIS feature class format. For example, the layer has different geometry types in one table.
You can try to use st-links tool (feature class to db) to load a feature class or shapefile into PostGIS and then add this table to arcMap.
There is a section in the manual about what kind geometry types are allowed in a table to be compatible with feature class format.