> I installed Ruby v1.6.3-1 and 1.6.4-1 (both InstallShield) and I can't
> use GTK with them:

Ditto here; it worked with Ruby 1.6.2 but not with the latter two. Is this
possibly related to the Cygwin version change? The Ruby 1.6.2 installer was
based around Cygwin-1.1.6 while the latter two are (I think) based on
Cygwin-1.1.8.