Hi,
The first option you mention - which is exporting the userform and then importing the .frm file - should be fine. If the import fails then a log file should be created which details the issues. I expect the reason it failed is that you can't have two modules with the same name in the same project. After you've exported the userform, rename the one in the VBE, then try importing the .frm. If you have any problems then show us the log details and hopefully we should be able to help.
The second option you mention is copying userforms within the VBA editor. I'm not aware of any built-in functionality to do this, so it would be a case of adding a new userform and then copying everything over. MZ Tools, which is an add-in I highly recommend, happens to have a "Copy Control with Code" option which would make this process slightly quicker.
The third option (which you don't mention) is to just have a single userform in your project and to create multiple instances of that userform at runtime. Given the information in the thread such as the fact that each userform in the series has the same controls, this is probably what I'd be doing here. Here's a generic VBA example to give you the general idea:
Code:
Dim ufmA As UserForm1, ufmB As UserForm1
Set ufmA = New UserForm1
Set ufmB = New UserForm1
ufmA.Caption = "First Userform"
ufmB.Caption = "Second Userform"
ufmA.Show vbModeless
ufmB.Show vbModeless
'etc...
Hope that helps...