Board Thread:Questions and Answers/@comment-5625597-20130401040550/@comment-5319459-20130401141330

Make sure you are using the new and up to date launcher (http://www.technicpack.net/download). If you are using the old launcher, you will not be playing a proper version of Tekkit Lite.

If you already have the new launcher, make sure you are running the recommended build 0.6.1.