Capella

[Philip Lewis]

I have been trying the Capella tutorial, and when I click to get the
Mix window, it only appears part way, and I get an error message: 

** Break during event processing! Standin event processor created. ***
**** Original event processor will continue when break loop exits. ****
> Error in process Initial: value NIL is not of the expected type NUMBER.
> While executing: RESIZE-OUTPUT-PANE

I built a version of CommonMusic with changes.txt dated 21 June 1995
with MCL 3.0 on a PowerBook 520. There were a number of error messages
which I did not note, all of the general kind, as I remember, "Method
so-and-so already exists. Replace?"  which I did.  What should I do?