长表错误

Question

\begin{longtable}{|lllll|}
\caption{Correlation analysis }
\hline
\multicolumn{5}{|c|}{\textbf{\begin{tabular}[c]{@{}c@{}}PO1: An ability to independently carry out research\\ development work to solve practical problems\end{tabular}}} \\ \hline
\endfirsthead
%
\endhead
%

\end{longtable}

当我编译此代码时，出现了诸如放错 \align、放错 \omit 等错误。