VBA error "No such application" when placing cell with tag set

Hey all. I've run into a problem and I hope someone here can help me. I've got a macro written that places a cell and then automatically sets the tags. However, when I call CreateCellElement2(), I'm getting a run-time error with code -2147218383 (80040c31) and text "No such application".

I searched online for that particular text, and sure enough, the first result was right here on this forum, from a few years back. But the person who made that posting never got an answer, they just settled for using key-ins. In my case, this process is designed to run multiple times, so key-ins aren't very attractive. Below is the code where I'm getting the error. For the record: ZP() is just an alias for Point3dZero. I've verified that the cellName var gets the correct cell name, that the correct cell library is attached, etc, etc.

'select which block
    Dim cellName As String
    cellName = Left(vp.cellName, Len(vp.cellName) - 3)
    'set up and create the cell
    Dim cellBlock As CellElement
    Set cellBlock = CreateCellElement2(cellName, ZP(), Point3dOne(), True, Matrix3dIdentity())
    'might need to specify the sheet name with activedesignfile.models(sheet name)
    ActiveModelReference.AddElement cellBlock
    cellBlock.Redraw msdDrawingModeNormal