RS-Linx OPC Server
The RS-Linx installation corrupts the OPC Foundation Core component and puts in an older version of the OPC Foundation Core components. Download them and reinstall them and restart the operating system if receive an RCW dll messing error.
If you are having trouble browsing RS-Linx go to Configure-Options-OPC and enable or disable the Classic RSLinx Fix for Browsing errors and select Apply Changes.
Also some versions of RS-Linx require you to select the + next to each branch first before selecting the branch to show the items.