We went through this the other day. It wasn't fun to fix on 26 computers.
You need to edit the NETHASP.INI file found in "C:\CADWorx Plant 2006\Assidrv" and then copy it to "C:\CADWorx Plant 2006" and "C:\Program Files\AutoCAD 200x".
The nethasp.ini file tells CADWorx where to look for the network lock. Just use my .ini file below as a guide to modify your local file.
Click the link below to open the PDF of my nethasp.ini file:
MY NETHASP.INI FILE