Unable to install - missing dependancy

I've just upgraded my Aptana and tried to install wireframe sketcher from update site. However, I'm getting this message

"Missing requirement: WireframeSketcher 2.5.0 (com.wireframesketcher.feature.group 2.5.0) requires 'org.eclipse.emf.ecore 0.0.0' but it could not be found".

Any suggestions as to what I can do to get past this, or where the missing dependancy can be obtained?

Hi Peter,

Did you follow the instructions for Aptana 3? You can find them here: http://wireframesketcher.com/install_details.html#aptana30

Let me know how it works for you.

Yep. You nailed it again Peter. I needed the Eclipse Helios update site enabled too. And as a bonus that sorted my issue with re-installing subversive!

Many thanks