Ref: "zenity: command not found" - load the 64-bit zenity extension
Ref: "failed to open r600: /usr/local/lib/dri/r600_dri.so" - use the apps gui to find which extension provides r600_dri.so, manually download the 32-bit extension, mount it (and its deps) and copy the libraries to the appropriate directories under /usr/local/lib32.
Note that I'm not sure the second part will work...