InnoSetup 4 CAN NO LONGER BE USED.

Besides that there's no future in relying on obsolete
versions of tools, version 5 introduced a vastly easier
way to manage the custom dialog pages Zope wants.  That
allowed getting rid of about 60 lines of inscrutable
Pascal code.  Of course the code that replaces them is also
inscrutable, but there's about 60 fewer lines of it to
torture future generations ;-).