In tracing thru the code looking for another problem I came upon what looks like an issue where in the function xos_kernel_Xoops2 the XOOPS and lib paths were not set correctly because there was no slash in front of the "browse.php"

Orig code:
function xos_kernel_Xoops2()
{
$this->paths['XOOPS'] = array(XOOPS_PATH, XOOPS_URL . 'browse.php');
$this->paths['www'] = array(XOOPS_ROOT_PATH, XOOPS_URL);
$this->paths['var'] = array(XOOPS_VAR_PATH, null);
$this->paths['lib'] = array(XOOPS_PATH, XOOPS_URL . 'browse.php');
$this->paths['modules'] = array(XOOPS_ROOT_PATH . '/modules', XOOPS_URL . '/modules');
$this->paths['themes'] = array(XOOPS_ROOT_PATH . '/themes', XOOPS_URL . '/themes');
}

I saw that since the XOOPS_URL had no trailing backslash that it concatenated the browse to the end of the XOOPS_URL causing an incorrect path.

Everywhere else in the code a slash is used in front of the path or file name that is being concatenated to the XOOPS_URL variable.