4
i faced the same problem, but managed to solve by simply following the installation instruction #4 properly, ie.
4. Make the directory of xoops_data/ writable; Create and make the directories of xoops_data/caches/, xoops_data/caches/xoops_cache/, xoops_data/caches/smarty_cache/ and xoops_data/caches/smarty_compile/ writable.