The following code is helpful for adding frame numbers to themes using the outer theme ''split'':
<code latex>
  \setbeamertemplate{footline}
  {%
  \hbox{\begin{beamercolorbox}[wd=.5\textwidth,ht=2.5ex,dp=1.125ex,%
                leftskip=.3cm,plus1fill,rightskip=.3cm]{author in head/foot}%
          \usebeamerfont{author in head/foot}%
          \insertframenumber\ /\ \inserttotalframenumber\hfill\insertshortauthor
  \end{beamercolorbox}%
  \begin{beamercolorbox}[wd=.5\textwidth,ht=2.5ex,dp=1.125ex,leftskip=.3cm,%
                rightskip=.3cm,plus1fill]{title in head/foot}%
          \usebeamerfont{title in head/foot}\insertshorttitle
  \end{beamercolorbox}}%
  \vskip0pt
  }
</code>