Beamer error with columns

Question

I want to put a picture in one column, some text in the other, and beneath all that some more text in a beamer style presentation. My frame looks like this:

\begin{frame}
\frametitle{Svemir dominiran tvari}
\begin{columns}
    \begin{column}{0.5\textwidth}
        \begin{itemize}
        \flushleft{\includegraphics[width=0.5\textwidth]{btph.eps}}
        \end{itemize}
    \end{column}
    \begin{column}{0.5\textwidth}
        \begin{itemize}
        \item Barionska asimetrija se izražava omjerom broja bariona i fotona
            \begin{equation}
            \eta=\frac{n_b-n_{\bar{b}}}{n_\gamma}=6.1\pm 0.3\times 10^{-10}.
            \end{equation}
        \end{itemize}
    \end{column}
\end{columns}
\begin{itemize}
    \item $n_b\Rightarrow$ \quad gustoća broja (stanja) bariona\\
    \item $n_{\bar{b}}\Rightarrow$ \quad gustoća broja antibariona\\
    \item $n_\gamma\Rightarrow$ \quad gustoća broja fotona
    $\frac{\zeta(3)}{\pi^2}g_\star T^3$
\end{itemize}
\end{frame}

When I compile it I get this error:

Something's wrong--perhaps a missing \item. \end{frame}

I looked at the code (which I c/p from another presentation that worked) and it looks the same. So why won't it compile? I have 11pt font in presentation, so that more text could fit.

Is the amount of text the issue? : EDIT: I have removed the itemize stuff, but now nothing shows on the slide :\

I don't see a thing on a slide now :\

Answer 1

You have a \begin{itemize} and \end{itemize} without an \item:

After reducing your code to a MWE by commenting out sections of code, the problem is more obvious:

\documentclass{beamer}

\begin{document}
\begin{frame}
\frametitle{Svemir dominiran tvari}
\begin{columns}
    \begin{column}{0.5\textwidth}
        \begin{itemize}
        \flushleft{\includegraphics[width=0.5\textwidth]{btph.eps}}
            % <----- There is no \item within this itemize environment
        \end{itemize}
    \end{column}
\end{columns}
\end{frame}
\end{document}

---

After adding the \item (and \RequirePackage[demo]{graphicx} since I do not have the image) with the the full code, I get:

Code:

\RequirePackage[demo]{graphicx}
\documentclass{beamer}

\begin{document}
\begin{frame}
\frametitle{Svemir dominiran tvari}
\begin{columns}
    \begin{column}{0.5\textwidth}
        \begin{itemize}
        \item \flushleft{\includegraphics[width=0.5\textwidth]{btph.eps}}
        \end{itemize}
    \end{column}
    \begin{column}{0.5\textwidth}
        \begin{itemize}
        \item Barionska asimetrija se izražava omjerom broja bariona i fotona
            \begin{equation}
            \eta=\frac{n_b-n_{\bar{b}}}{n_\gamma}=6.1\pm 0.3\times 10^{-10}.
            \end{equation}
        \end{itemize}
    \end{column}
\end{columns}
\begin{itemize}
    \item $n_b\Rightarrow$ \quad gustoća broja (stanja) bariona\\
    \item $n_{\bar{b}}\Rightarrow$ \quad gustoća broja antibariona\\
    \item $n_\gamma\Rightarrow$ \quad gustoća broja fotona
    $\frac{\zeta(3)}{\pi^2}g_\star T^3$
\end{itemize}
\end{frame}
\end{document}