Eclipse: 32-bit GWT (GTK) configuration on x86_64 arch to avoid "Failed to load module"/"wrong ELF class"

If you get "Gtk-Message: Failed to load module "canberra-gtk-module": /usr/lib/gtk-2.0/modules/libcanberra-gtk-module.so: wrong ELF class: ELFCLASS64" messages on the console when you launch a Run/Debug Configuration of your GWT Web Application, you should set the value of the environemtal variable GTK_PATH to /usr/lib32/gtk-2.0:

...whereby ${GTK_32_PATH} should have the value /usr/lib32/gtk-2.0. Eventuall you have to install the ia32-libs-gtk package to make /usr/lib32/gtk-2.0 available.

You haven't to use the x32 JDK/JRE as your default Java VM for the whole x64 system but install ia32-sun-java6-bin package and set this VM as your default JRE only in Eclipse (for the projects) but not for Eclipse itself: