A few files in the source are only readable by root: ikiwiki/basewiki/favicon.ico ikiwiki/doc/logo/ikiwiki_large.png ikiwiki/doc/logo/ikiwiki.svgz ikiwiki/templates/atomitem.tmpl ikiwiki/templates/atompage.tmpl
This means that (depending on installation) maybe the permissions are wrong for the final install. So when ikiwiki is ran (as non-root) it fails.