I had the same problem. I commented out line #44 $dirname = str_replace(".", "", $dirname); in xoopslists.php. It appears this line removes the "." from the relative path of ./install/language/ to the invalid path of /install/language/. I am not sure what the purpose of removing the period is this instance.

After that the install worked fine. But now I am having a problem where I only get blank pages when I try to load index.php.