Your a developer, you say? So your Java 7 version, its the JDK and not JRE, right? Because JDK has been known to cause issues. If thats the case, I'd recommend removing the JDK and replacing it with the recommended apple version for 7, and seeing if the issue resolves.
Tech Jargon time, since you've done java dev. We are getting a reflection invoke error deeper in the report, and that would indicate that something in the calling of the function has broke, as opposed to the function itself, IE java cannot find the normal 64 bit libraries that it wants, as its following the technic pack instruction set for them. JRE has a different structure, from my knowledge, that JDK, which means if JDK is the primary version of java 7, then the directions that technic pack gives would be pointing somewhere completely different, than they would be for regular java. End of tech rant.