Vorteyga

This worked for me: 1) Run the Tekkit Launcher. 2) Find the mod pack you wish to fix on the left edge of the window. 3) Hit the small cogwheel on the lower left corner of said mod pack's image. 4) A window should pop up with a few options. Hit the "Reset Pack" button in the lower left corner. 5) Launch the mod pack. It updated itself upon launching after reset, and then it worked just fine. Hope this helps!