[V8i VBA] Reference Attachments query (RefFullPathStored )

I'm starting a new project and was looking through existing threads regarding reference attachments and I discovered the following post with a sample procedure.

https://communities.bentley.com/products/programming/microstation_programming/f/19570/p/69621/181883#181883

I'm curious to see what the procedure does as it contains some lines of code I haven't yet encountered. It appears to need a form and a listbox so I created those.

I get an error on the following line:

status = GetCExpressionValue("RefFullPathStored (" & oAttachment.MdlModelRefP & " )", "RefClippingUtil")

Though I have seen it in threads in the past, I'm not familiar with GetCExpressionValue but I have looked at the VBA help section on it though I wont pretend to understand what its telling me.

My question is, am I getting the error because I am missing a specific file or additional procedure(s) or something entirely different?