First, post in this section. http://forums.technicpack.net/index.php/board,5.0.html
Use this report format: http://forums.technicpack.net/index.php/topic,2797.0.html
And look at common problems and solutions.
Finally, update your Java to Java 7, located here: http://www.oracle.com/technetwork/java/javase/downloads/jre-7u3-download-1501631.html
Accept the agreement and download the version for your PC.
Finally, delete your .techniclauncher folder (after backing up worlds), and re-install from the launcher.