Most likely this means that the OPC server is not properly installed on the target computer, but more details are needed in order to be sure. OPC server is a COM object, and it needs to be registered as such. This is usually taken care of automatically by its installation, but if things fail, it might be possible to register it manually from command line: Do "<filename> /RegServer" if it is an EXE, or "RegSvr32 <filename>" if it is a DLL.
The details I am looking for are:
1. The client and the server are on different computers, right?
2. Is the current operating system on the server 32bit or 64bit?
3. Was the original OS on the server side 32bit or 64bit?
4. What was the procedure used to install the server?
5. Please provide details of the exception: Full message, value of its .Source property, and the same about its .InnerException, if non-null.
6. Have you tried some OPC client to connect to the server *from the same machine where the server is located (locally)*, and what were the results? Please try that if not done yet. Can be the demo client app that comes with QuickOPC.
7. Have you tried some other OPC client to connect from the client machine to the server and what were the results?
Note: The SubscribeItem call always succeeds unless their is a usage (programming) error (such as null argument). This is by design. All errors are then reported through the data change notifications - the way you are seeing.
Thank you
