It works fine in Word 2007.

I will try in my office on Monday on Word 2000.

Yann was telling us:
Yann nous racontait que :

Did you get the error when executing step by step or when executing
normally? Some code cannot be executed step by step, like the userform
naming code, but it runs fine if executed normally.

At least, this is what I have observed with Word 2003.

Once you run your code, VBE constructor has allocated used userform names in
cache during a VBE session.
If you want to create a new userform (eventhough it is deleted physically
from the VBcomponents collection) using a previously used name in the same
VBE session, you'll see this behaviour.

Y'll have to use an enumerator to by pass this, like in below sequence.
Note: pass the incremented enumerator to the name property of yr newly
created userform.

Kindly feedback the results.

Sub BuildMyForm()
Static iEnum as integer
  Set mynewform = _
     ActiveDocument.VBProject.VBComponents.Add(vbext_ct_MSForm)
     With mynewform
        .Properties("Height") = 246
        .Properties("Width") = 616
        .name = "HelloWord_" & Cstr(iEnum)
        .Properties("Caption") = "This is a test"
     End With
End Sub

--
Krgrds,
Perry

System:
Vista/Office Ultimate
VS2005/VSTO2005 SE