Panface

Sure you have installed Java 7? And if it doesn't show up in spotlight have you tried to go into system options/preferences and looked there for Java settings?

Had same prob. Also ran server on mac with Java 7 and when i later tried to start client it crashed Fix for me was, - In spotlight search for java settings/preferences, and then you should get a list with different java versions. - Drag the Java 6 32/64 (Apple Inc.) to the top of the list and then close and start Tekkit. That way you can keep Java 7 installed too :)