Hi brjtaylor, you unlucky one.
There is unfortunately no fix for your problem. However, as a workaround you can use my savegames as others already did.
Here is the level 15 start file which will help you to overcome the problem you encountered. However, more problems are about to follow. Use the savegames in
this directory to overcome them as well. Once you have reached level 16, all should be ok again.
Good luck!