\documentclass[hyperref={pdfpagelabels=false}]{beamer}
% By using hyperref={pdfpagelabels=false} you get rid off:
% Package hyperref Warning: Option `pdfpagelabels' is turned off
% (hyperref) because \thepage is undefined.
% Hyperref stopped early
%
\usepackage{lmodern}
% Using lmondern and you get rid off this:
% LaTeX Font Warning: Font shape `OT1/cmss/m/n' in size <4> not available
% (Font) size <5> substituted on input line 22.
% LaTeX Font Warning: Size substitutions with differences
% (Font) up to 1.0pt have occurred.
%
% If \titel{$B!D(B} \author{$B!D(B} come after