The great datatool package seems to have no problem with spaces in headers.
\documentclass{article}\usepackage{datatool}\thispagestyle{empty}\begin{document}\DTLloadrawdb{posts}{forum_posts_table_1.csv}\renewcommand{\dtlheaderformat}[1]{\parbox[t]{5em}{\bfseries #1}}\DTLdisplaydb{posts}\end{document}