Error: Mixin box-shadow doesn't have the following arguments: $shadow_1, $shadow_2.

When I run compass I get the the error:
Error: Mixin box-shadow doesn't have the following arguments: $shadow_1, $shadow_2.
I installed the gem "susy" for compass after looking at your config.rb file and still get this error. Any idea what's happening here?

Attached the entire message in the generated shadows.css file.