I too think it's a problem with the installation of the extension. Download the SOA extension to yout pc (http://download.oracle.com/otn-pub/jdeveloper/220.127.116.11.0/extensions/soa-jdev-extension.zip) and start jdev form a command shell (jdeveloper/bin/jdev.exe or jdev64.exe for windows). install the extension from the local file and don't restart jdev when asked after the installation. Close jdev and start it again from the command shell. You should then see any messaged which the installer generates.