the style validates, you're probably just doing something wrong with validation.
Are you using Zotero or Mendeley?

your style is in csl 0.8.1. Mendeley can only use csl 1.0 styles (Zotero converts old styles internally). You can auto-update the style following the instructions here:
http://citationstyles.org/downloads/upgrade-notes.html#updating-csl-0-8-styles

Please, next time you have a question do specify which software you are using.

https://gist.github.com/1217338
the online tool choked on the em-dashes.

maybe you need to change the <id> and the name - but this is really a Mendeley issue, contact their support, the style validates as csl 1.0.

http://validator.nu/?doc=https://gist.github.com/raw/1217338/62387312d736b888a9e5b6d447ce07f889e05399/martyna.csl&charset=UTF-8&schema=https://github.com/citation-style-language/schema/raw/v1.0/csl.rnc&laxtype=yes

and should work correctly with all software running csl.