Unable to run Dia on iMac

[Ralph Tindell <ralph stanley tindell gmail com>]

I have I tried a fresh install of Dia on my iMac and have a recurring problem.  First of all, XQuartz 2.7.11 is installed.  Secondly, the folder /Applications/Dia.app/Contents/MacOS is empty, which seems weird to me.  Finally, when I execute /Applications/Dia.app/Contents/Resources/bin/dia I get the following error:

Ralphs-iMac:bin ralph$ ./dia
Warning: AppleCollationOrder setting not found, using AppleLocale.
Setting Language: en.UTF8

(process:71973): Gdk-WARNING **: locale not supported by C library

(process:71973): Gtk-WARNING **: Locale not supported by C library.
Using the fallback 'C' locale.

(dia-bin:71973): Gtk-WARNING **: cannot open display: /private/tmp/com.apple.launchd.x81Gh3JDGu/org.macosforge.xquar