SOLVED: a reboot did the trick! Thank you Jesus Eguiluz. -- View this message in context: http://mono.1490590.n4.nabble.com/Gtk-sample-app-built-on-Ubuntu-11-4-rebuilt-on-Win7-fails-to-run-tp3509167p3509518.html Sent from the Mono - Gtk# mailing list archive at Nabble.com.