MacTeX pgfkeys/tikz package fails [closed]

the document listed below, (taken from here: texample.net) fails on my system (running MacTeX 2011) with the error:

Package pgfkeys Error: I do not know the key '/tikz/drop shadow' and
I am going to ignore it. Perhaps you misspelled it.


I've checked my packages using the TeX Live Utility and they all seem to be up to date. Any ideas on what I might be doing wrong? Thanks.

The document:

\documentclass{article}

\usepackage{tikz}
\usepackage{pgf-umlsd}
\usepgflibrary{arrows} % for pgf-umlsd
\begin{document}

\begin{figure}
\centering

\begin{sequencediagram}
\newinst{ctr}{}{SimControlNode}
\newinst{ps}{}{PhysicsServer}
\newinst[1]{sense}{}{SenseServer}

\begin{call}{ss}{Initialize()}{sense}{}
\end{call}
\begin{sdloop}{Run Loop}
\begin{call}{ss}{StartCycle()}{ctr}{}
\begin{call}{ctr}{ActAgent()}{sense}{}
\end{call}
\end{call}
\begin{call}{ss}{Update()}{ps}{}
\begin{call}{ps}{PrePhysicsUpdate()}{sense}{state}
\end{call}
\begin{callself}{ps}{PhysicsUpdate()}{}
\end{callself}
\begin{call}{ps}{PostPhysicsUpdate()}{sense}{}
\end{call}
\end{call}
\begin{call}{ss}{EndCycle()}{ctr}{}
\begin{call}{ctr}{SenseAgent()}{sense}{}
\end{call}
\end{call}
\end{sdloop}
\end{sequencediagram}

\caption{UML sequence diagram demo.}
\end{figure}
\end{document}


Update: I found the answer: The packages were wrong - for my system running pgf-umlsd.sty v0.5 atleast. They should have been...

\documentclass{article}

\usepackage{tikz}

Additionally, the command \begin{sdloop}{Run Loop} now needs to be \begin{sdblock}{Run Loop}.