All basic macros for LaTeX is contained with latex.ltx. There is a version-control component (originally from ltvers.dtx) which checks whether your existing latex.ltx is too old:
%%% From File: ltvers.dtx
\def\fmtname{LaTeX2e}
\edef\fmtversion{2011/06/27}
\iffalse
\def\reserved@a#1/#2/#3\@nil{%
\count@\year
\advance\count@-#1\relax
\multiply\count@ by 12\relax
\advance\count@\month
\advance\count@-#2\relax}
\expandafter\reserved@a\fmtversion\@nil
\ifnum\count@>65
\typeout{^^J%
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!^^J%
! You are attempting to make a LaTeX format from a source file^^J%
! That is more than five years old.^^J%
!^^J%
! If you enter <return> to scroll past this message then the format^^J%
! will be built, but please consider obtaining newer source files^^J%
! before continuing to build LaTeX.^^J%
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!^^J%
}
\errhelp{To avoid this error message, obtain new LaTeX sources.}
\errmessage{LaTeX source files more than 5 years old!}
\fi
It checks whether \fmtversion is older than 65 months. If it is, then it prints the message you report, otherwise it continues without problem.
You either didn't install the latest version of MiKTeX 2.9 properly, or there's another distribution interfering with it. Re-install it correctly to obtain an up-to-date version.
Alternatively, if this does not work (for whatever reason), you can edit latex.ltx* and modify the condition \ifnum\count@>65 to (say) \ifnum\count@>100. However, it's best to properly install and update your distribution.
* Perhaps located in C:\Program Files\MiKTeX 2.9\tex\latex\base.
