I really don't know anything about Makerware software. You should contact makerbot support, if you have their printer or maybe some makerbot forum, where people use the same software.
My guess is, that all the hair is confusing your software. I have made some other hairy things, try slicing those, just to see if it works or not.
Another option is to try different slicer. It will probably take you some time to configure it correctly.
Slic3r says it is compatible with Makerbot.
Simplify3d would probably be best and easiest, but it is expensive. Although you can get a refund after two weeks if you don't like it. That should be enough time to print a lion.