PGFPlots \addplot cannot read regression column [closed]

Question

I am trying to plot a small dataset and a regression line for it.

Here is my MWE:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{tikz}
\usepackage{pgfplots}
\usepackage{filecontents}

\begin{filecontents}{dtat.dat}
X Y
1 9
2 8
3 4
4 2
\end{filecontents}

\begin{document}

\begin{tikzpicture}
  \begin{axis}
    \addplot table [x=X,y=Y] {dtat.dat};
    \addplot table [x=X,y={create col/linear regression={y=Y}}] {dtat.dat};
  \end{axis}
\end{tikzpicture}

\end{document}

Though I believe my file accurately reflects the examples in the manual and online, I get the following error:

Package pgfplots Error: Sorry, could not retrieve column 'create col/linear r egression={y=Y}' from table 'dtat.dat'. Please check spelling (or introduce nam e aliases)..

The data plots accurately, but the regression line basically plots the x values (or line numbers?) against themselves and is clearly incorrect. Any help resolving this (probably simple user) error would be greatly appreciated.

In case it makes a difference, I am using TeX Live on Ubuntu and Linux Mint, which are both fully up to date). The version of pgfplots.sty is 1.2.2 from 2009/02/14. (Woefully outdated I'm guessing...?)

Answer 1

Posted as comments by OP @cuz:

Ah...version 1.2.2. And I see that linear regression was added in 1.5. Guess its time to work out how to update a sty file independent of the repositories. Thanks. A simple issue I didn't think to check.

and

Upgraded to TeXLive 2012 and updated the pgfplots package using these instructions. Works great now. Thanks again for solving the first problem I couldn't work out on my from the forums.