Why am I getting an elisp error?

I just installed yasnippets and addeded these snippets for latex https://github.com/madsdk/yasnippets-latex/

When I try to expand a snippet like "eq" I get the following:

\begin{equation}
  \label{[yas] elisp error!}

\end{equation}

Why is this happening,开发者_如何学JAVA and how do I fix it?

The debug-on-error didn't do anything, I guess because of the good-grace thing. But turning on reftex-mode fixed the problem.