For Excel worksheets with RTD functions referring to Connectivity RTD Server, you need install following files:
You will find them under the Bin subdirectory in the installation directory of the product.
In addition, you need to register the OpcLabs.OfficeConnector.dll assembly using the Assembly Registration tool (Regasm.exe). The Assembly Registration tool is a part of .NET Framework, and is therefore available on every computer that has the .NET Framework installed.
For more information, please refer to http://msdn.microsoft.com/en-us/library/tzat5yw6(v=vs.110).aspx. It is recommended that you use the /codebaseoption when registering the assembly.