If you want to "include" a file, use \input, not \include :-)

The \include command is used in conjunction with the \includeonly command for selective inclusion of files. The file argument is the first name of a file, denoting file.tex. If the file is also in the file list of the \includeonly command or if there is no \includeonly command, the \include command is equivalent to

\clearpage \input{file} \clearpage

except that if the file file.tex does not exist, then a warning message rather than an error is produced.