From the NI knowledge base...
Problem: How do I enable LabVIEW as an ActiveX Server?
Solution: Under Edit >> Preferences >> Server: Configuration, select ActiveX as a protocol and enable all server resources. Under Edit >> Preferences >> Server: Exported VIs, list the name of all VIs that can be accessed remotely. You can include the full path to the VI, or just list its name. Wildcard characters are valid. You can explicitly deny access to certain VIs by clicking the Deny Access button. Note that changes to the Server will not take effect until LabVIEW is relaunched.