Hi Robert
LabVIEW 7.1 implements some new security features dealing with DCOM that were not in 7.0. Windows is moving in this direction, and National Instruments decided to follow suit. 7.1 requires a certain level of authentication from the server. If this is the issue in your case, it can be resolved with the following steps (this is for Windows XP; CE will probably be different):
1. On the computer hosting your OPC server select "Start >> Settings >> Control Panel >> Administrative Tools >> Component Services.
2. On the tree on the left, expand "Component Services >> Computers >> My Computer >> DCOM Config.
3. Your OPC server should be registered as one of these items. Right-click on your server and select "Properties."
4. On the "General" tab, change the "Authentication Level" to "Connect."
If this property is already set to Connect or Default (and the default setting is Connect) then this will have no effect.
You can also try checking some of the other settings:
1. On the computer hosting your OPC server select "Start >> Settings >> Control Panel >> Administrative Tools >> Component Services.
2. On the tree on the left, expand "Component Services >> Computers >> My Computer
3. Right-click on My Computer and select "Properties."
4. On the "Default Properties" tab, make sure "Default Impersonation Level" is set to "Identify."
You may also want to look at the "COM Security" tab to make sure your computer has the right permissions.
If all else fails, you can try adding the line "ole.AuthnLevel = 1" to the LabVIEW.ini file. This should reverse some of the changes to 7.1.
regards
Manuel Wielander
National Instruments