Its not clear what you are trying to do. <ButtonRelease-1> would used for binding the left mouse button release to something. <1> would be when it is pressed, or I think longer form <Button-1>. To click on a normal Button, you don't have to fiddle with mouse bindings, just plug in a sub to be called. Post some code so that we can see what's going on.

I looked in Buttom.pm. It uses these mouse bindings internally so its possible to see an error like that from the standard widget - the button up routine changes relief of the clicked button back to what it was etc.