The name prompt is used when searching for a file, because LabVIEW anticipates that you will be able to find a specific file only if you know the name (otherwise, how could you work out which file is being searched for?)
When you use the CLFN (call library function node) you are specifying the library directly. LabVIEW cannot provide an appropriate prompt because you could be wanting to select anything!
If you didn't save the code (or you have a backup using source code control) then you can close it without saving, and reload it. Then, it will still be searching for the previously selected library.
If you already saved with the new library selected, and it is not the correct library, and you do not have an older copy of the code with the correct name specified, then you must work out the correct library yourself using the context (what function are you looking for, etc) and the documentation available with the DLLs.
I hope this helps although I fear it may not be what you wanted to hear. Perhaps someone else has another suggestion or explanation.