Without the template it is difficult to imagine what is going on, but it seems probable that it relates to the fact that you haven't unloaded the form after use. I prefer to call a new form from the macro that calls the form, so in your template, you need an ordinary module with the code below (which assumes your userform is called frmMyForm and it has two option buttons optLetter and optFax and that it has two command buttons btnCancel and btnOK.
Option Explicit
Sub RunProcess()
Dim oFrm As New frmMyForm
With oFrm
.OptLetter.Value = True 'set the initial value
.Show
If .Tag = 0 Then GoTo lbl_Exit 'Cancel clicked
Application.ScreenUpdating = False
If .OptLetter.Value = True Then
Application.Templates(ThisDocument.FullName).BuildingBlockEntries("1 - Letter").Insert Where:=Selection.Range, _
RichText:=True
ElseIf .OptFax.Value = True Then
Application.Templates(ThisDocument.FullName).BuildingBlockEntries("2 - Fax Cover").Insert Where:=Selection.Range, _
RichText:=True
End If
Application.ScreenUpdating = True
End With
Unload oFrm
lbl_Exit:
Set oFrm = Nothing
Exit Sub
End Sub
Your Private Sub Document_New() macro should call the above Macro e.g.
Option Explicit
Private Sub Document_New()
ModMain.RunProcess
End Sub
and the userform code should be
Option Explicit
Private Sub btnCancel_Click()
Hide
Tag = 0
End Sub
Private Sub btnOK_Click()
Hide
Tag = 1
End Sub
which leaves the ribbon captions, for which you will need the CustomUI editor. Close Word and open the add-in template with the ribbon in the editor. You will see two sets of code
The second is a sub set of the first and both will need to be changed. The labels are shown below
<customUI xmlns="http://schemas.microsoft.com/office/2009/07/customui">
<ribbon>
<tabs>
<tab idMso="TabHome">
<group id="CompanyGroup001" insertBeforeMso="GroupClipboard" label="Document">
<button id="CompanyTemplateBtn001" imageMso="FileNew" size="large" label="Create Company Form" onAction="CompanyTemplateBtn"/>
</group>
</tab>
</tabs>
</ribbon>
<backstage>
<tab idMso="TabOfficeCompany" visible="false" />
<tab id="tabCompanyTemplateNew" insertAfterMso="TabInfo" label="Company Form" columnWidthPercent="25">
<firstColumn>
<group id="CompanyGroup000" helperText="
Create a new blank document based on the Company Form" >
<primaryItem>
<button id="CompanyTemplateBtn000" label="Company Form" imageMso="FileNewBlankDocument" isDefinitive="true" onAction="CompanyTemplateBtn" />
</primaryItem>
</group>
</firstColumn>
</tab>
</backstage>
</customUI>
and
<customUI xmlns="http://schemas.microsoft.com/office/2006/01/customui">
<ribbon>
<tabs>
<tab idMso="TabHome">
<group id="CompanyGroup001" insertBeforeMso="GroupClipboard" label="Document">
<button id="CompanyTemplateBtn001" imageMso="FileNew" size="large" label="Create Company Form" onAction="CompanyTemplateBtn"/>
</group>
</tab>
</tabs>
</ribbon>
</customUI>