I'd like to show a 'Please wait message' during the Excel macro does
something in the background.

  dim frm as frmWaitForm
  set frm = new frmWaitForm
  load frm
  frm.show false                              'false parameter makes
form display non-modally, i.e.do not wait for OK button to be pushed.
[long running process here.]
  frm.hide
  unload frm
  set frm = nothing

Does someone know why I get an error in the line
  frm.show false

Compile error: Wrong number of arguments or invalid property assignment.

Does someone have any idea what I'm doing wrong?

Any help is very appreciated
Stefan

<< frm.show false >>
will work only in Office 2000.

However for your objective (as I understand it) you can simply have:

----------------
Sub MyMacro()
'...long procedure doing lots of funcy things
End Sub

Sub startMacro()
Userform1.Show
End Sub
-----------------

and in the userform:

Private Sub Userform_Activate()
DoEvents  'To allow it paint itself first
Call MyMacro
End Sub
------------------

HTH
Stratos