beamer struggling with subfig (subfig doesn't work!)

Question

I want to put multiple figures in one frame. I am trying different combinations but neither works. I used subfigure (worked) but I didn't manage to put in a proper way the figures.

As I read, it's better to use subfig (and also it's easier for me), but it seems subfig always throw a lot of errors (and it opens the subfig.sty file).

\documentclass[10pt,blue]{beamer}

 \setbeamertemplate{navigation symbols}{}
 \usepackage[caption=false]{subfig}



\usepackage{fontspec}
\setsansfont{DejaVuSans}
\usepackage{polyglossia}
\setmainlanguage{greek}
 \setotherlanguage{english}

\usepackage{url}


 %\usepackage{caption}%,subcaption}



 \usepackage{ graphicx, amsmath, amssymb, lettrine}


\newcommand{\EN}[1]{\foreignlanguage{english}{#1}}
\mode<presentation>

\begin{document}

\begin{frame}
\frametitle{\EN{title}}
\setbeamercovered{transparent}


\begin{figure}
\centering

\subfloat[][]{\includegraphics[scale=0.55]{cad-}\label{lab1}}
\subfloat[][]{\includegraphics[scale=0.55]{grid}\label{lab2}}
\subfloat[][]{\includegraphics[scale=0.55]{grid}\label{lab3}}
\subfloat[][]{\includegraphics[scale=0.55]{grid}\label{lab4}}
\subfloat[][]{\includegraphics[scale=0.55]{grid}\label{lab5}}
\subfloat[][]{\includegraphics[scale=0.55]{grid}\label{lab6}}

%\caption{\EN{text} \protect\subref{lab1} \EN{some text} 
%  \protect\subref{lab2} \EN{ text}}

\end{figure}

\end{frame}

\end{document}

---------------UPDATE----------------------------------

Even with that setup doesn't work.. It seems subfig doesn't work. It opens the subfig.sty file.

\documentclass{beamer}

\usepackage[utf8x]{inputenc}
\usepackage{default}
\usepackage[caption=false]{subfig}


\begin{document}
Hello
\end{document}

---------------UPDATE 2---------------------------------------

Beginning of log file:

This is XeTeX, Version 3.1415926-2.2-0.9995.2 (TeX Live 2009/Debian) (format=xelatex 2012.7.6)  9 SEP 2012 17:49
entering extended mode
 %&-line parsing enabled.
**forstack.tex
(./forstack.tex
LaTeX2e <2009/09/24>
Babel <v3.8l> and hyphenation patterns for english, usenglishmax, dumylang, noh
yphenation, ibycus, monogreek, greek, ancientgreek, loaded.
(/usr/share/texmf-texlive/tex/latex/graphics/graphicx.sty
Package: graphicx 1999/02/16 v1.0f Enhanced LaTeX Graphics (DPC,SPQR)

(/usr/share/texmf-texlive/tex/latex/graphics/keyval.sty
Package: keyval 1999/03/16 v1.13 key=value parser (DPC)
\KV@toks@=\toks14
)
(/usr/share/texmf-texlive/tex/latex/graphics/graphics.sty
Package: graphics 2009/02/05 v1.0o Standard LaTeX Graphics (DPC,SPQR)

(/usr/share/texmf-texlive/tex/latex/graphics/trig.sty
Package: trig 1999/03/16 v1.09 sin cos tan (DPC)
)
(/etc/texmf/tex/latex/config/graphics.cfg
File: graphics.cfg 2009/08/28 v1.8 graphics configuration of TeX Live
)
Package graphics Info: Driver file: xetex.def on input line 91.

(/usr/share/texmf-texlive/tex/xelatex/xetex-def/xetex.def
File: xetex.def 2009/11/22 v0.94 LaTeX color/graphics driver for XeTeX (RRM/JK)

))
\Gin@req@height=\dimen102
\Gin@req@width=\dimen103
)
(/usr/share/texmf/tex/latex/beamer/base/beamer.cls
(/usr/share/texmf/tex/latex/beamer/base/beamerbasercs.sty
Package: beamerbasercs 2007/01/28 (rcs-revision 1.4)
)
Document Class: beamer 2007/03/11 cvs version 3.07 A class for typesetting pres
entations (rcs-revision 1.70)
(/usr/share/texmf/tex/latex/beamer/base/beamerbasemodes.sty

The first errors:

! Missing \endcsname inserted.
<to be read again> 
                   \ext@figure 
l.298 ...ined{c@subfigure}{\newsubfloat{figure}}{}

The control sequence marked <to be read again> should
not appear between \csname and \endcsname.


! LaTeX Error: Missing \begin{document}.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              

l.298 ...ined{c@subfigure}{\newsubfloat{figure}}{}

You're in trouble here.  Try typing  <return>  to proceed.
If that doesn't work, type  X <return>  to quit.

! Extra \endcsname.
\@ifundefined ...dafter \ifx \csname #1\endcsname 
                                                  \relax \expandafter \@firs...
l.298 ...ined{c@subfigure}{\newsubfloat{figure}}{}

I'm ignoring this, since I wasn't doing a \csname.

! Missing \endcsname inserted.
<to be read again> 
                   \ext@figure 
l.298 ...ined{c@subfigure}{\newsubfloat{figure}}{}

The control sequence marked <to be read again> should
not appear between \csname and \endcsname.

! Extra \endcsname.
\newcounter ...ifdefinable \csname c@#1\endcsname 
                                                  {\@definecounter {#1}}\@if...
l.298 ...ined{c@subfigure}{\newsubfloat{figure}}{}

I'm ignoring this, since I wasn't doing a \csname.

Answer 1

The following, modified form of your MWE (i) doesn't throw any errors and (ii) manages to place all six "figures" side-by-side. Because I don't have access to the files cad-[.pdf] and grid[.pdf], note that I had to load the graphicx package with the demo option set (which will just create a black blob in lieu of loading an actual graphics file).

Furthermore, since I have no idea what the natural scale of your graphics files may be, I've replaced all [scale=0.55] instructions with [width=1.4cm] instructions. I've also inserted various \hspace{1mm} instructions to create some separation between the subfloats.

\RequirePackage[demo]{graphicx} % remove this in final version
\documentclass[10pt,blue]{beamer}

\setbeamertemplate{navigation symbols}{}
\usepackage[caption=false]{subfig}

\usepackage{fontspec}
\setsansfont{DejaVuSans}
\usepackage{polyglossia}
\setmainlanguage{greek}
\setotherlanguage{english}

\usepackage{url}

%\usepackage{caption}%,subcaption}

\usepackage{ amsmath, amssymb, lettrine} % don't load graphicx package again -- beamer already does that

\newcommand{\EN}[1]{\foreignlanguage{english}{#1}}
\mode<presentation>

\begin{document}

\begin{frame}
\frametitle{\EN{title}}
\setbeamercovered{transparent}

\begin{figure}
\centering

\subfloat[][]{\includegraphics[width=1.4cm]{cad-}\label{lab1}}
\hspace{1mm}
\subfloat[][]{\includegraphics[width=1.4cm]{grid}\label{lab2}}
\hspace{1mm}
\subfloat[][]{\includegraphics[width=1.4cm]{grid}\label{lab3}}
\hspace{1mm}
\subfloat[][]{\includegraphics[width=1.4cm]{grid}\label{lab4}}
\hspace{1mm}
\subfloat[][]{\includegraphics[width=1.4cm]{grid}\label{lab5}}
\hspace{1mm}
\subfloat[][]{\includegraphics[width=1.4cm]{grid}\label{lab6}}

%\caption{\EN{text} \protect\subref{lab1} \EN{some text} 
%  \protect\subref{lab2} \EN{ text}}

\end{figure}
\end{frame}
\end{document}