We put the arx files in this order within the ACAD.RX:
VueExporter.arx
CADWorxEquipment.arx
CADWorxStructure.arx
CADWorxPlant.arx
sls.arx

After that be sure you have the following additional paths in your profile:
Support file search paths:
C:\cadworx 2018\equipment\support
C:\cadworx structure 2018\structure\support
C:\cadworx structure 2018\structure\blocks
C:\cadworx structure 2018\structure\borders

TRUSTED LOCATIONS path:
C:\CADWorx 2018\Equipment\Support
C:\CADWorx 2018\P&ID\Support
C:\CADWorx Structure 2018\Structure\Support