I'm guessing that you didn't use a commandbutton from the Control toolbox
toolbar. I'm guessing that you used a button from the Forms toolbar.
If you select the button/commandbutton, then look at the namebox (to the left of
the formula bar), what do you see?
Is it a name like: Button 1
or a name like: CommandButton1
If you rightclick on the button, do you see an option for Assign macro? If you
see either "button 1" in the namebox or the option for Assign macro, then your
button is from the Forms toolbar.
You can use that button, but it's more work. You'll have to re-assign the macro
that's in the correct .xls file.
But in this case, I'd delete that forms toolbar button and replace it with
commandbutton from the Control toolbox toolbar.