I can't confirm for sure because I was only reading into the error message OP was getting, but none of the examples I found online showed using Inline::C within a module, so I traded __END__ for __DATA__ which the error clearly stated it was looking for, and I suspect the module close was causing the grief.

I'm hoping one of the experienced Inline Monks has run into this before, and can clarify. My test was literally just a guess and some playing :) On Windows, I'd think that one would need to install a C compiler (unless ActiveState and/or Strawberry come with one build-in).

Update: read Re: Using module with c code in perl program. by AnonyMonk, as my suspicions regarding end-of-module are definitely confirmed by the documentation, per that post.