Can you try editing qa-install.php to add the query? At line 131 (starting $errorhtml .= ...) change to
$errorhtml .= "A Question2Answer database query failed when generating this page.\n\nA full description of the failure is available in the web server's error log file.\n\n".qa_html($pass_failure_query."\n\nError ".$pass_failure_errno.": ".$pass_failure_error."\n\n");
That will show you the query error. Post it here and I should be able to help.