Texmaker and TeXstudio ⇒ Figures, subfigures, wrap figures

[Dmytro]

Dear all,

I have been playing around with figures and subfigures environments, but have not succeeded much. Basically, in order to insert figures (and subfigures) and at the same time wrap them up around the passage I have utilised the following packages:
\usepackage{graphicx}
\usepackage{wrapfig}
\usepackage{caption}
\usepackage{subcaption}

So that to place the figure/s I have used the next environment:
\begin{wrapfigure}[h]{0.5\textwidth}
\begin{center}
\begin{subfigure}
\includegraphics[width=0.2\textwidth]{title1.png}
\caption{tyre-smooth surface interaction}
\label{fig:tyre1}
\end{subfigure}

\begin{subfigure}
\includegraphics[width=0.5\textwidth]{title2.png}
\caption{tyre-smooth surface interaction}
\end{subfigure}
\end{center}

\end{wrapfigure}

However, when I compile the code, long list of errors are popping up in relation to one of those environment lines like as:
- missing \endcsname inserted;
- missing number treated as zero;
- illegal unit of measure;
Can you please help me to identify the hidden problem? Thanks immensely in advance! Cheers!