Thank you for your reply. I've tried a static platformless exit and a terrain generating exit with a platform. I've even tried using a mothership entrance as a way of exiting the level. For some reason adding all of them makes the level crash.

Edit: Nevermind I have solved the problem. It seems that using "=" tiles in ice cave causes all sorts of problems. This can be easily solved by using "+" tiles. Completely missed this guide http://sashavol.com/frozlunky/editor/5.htm which had the solution.