multi-domain plugin generates error

When I have activated multi-domain and created a new site it is throwing following error.

Warning: Creating default object from empty value in /home/umruweb/public_html/wp-includes/ms-functions.php on line 1502

Warning: Cannot modify header information - headers already sent by (output started at /home/umruweb/public_html/wp-includes/ms-functions.php:1502) in /home/umruweb/public_html/wp-includes/pluggable.php on line 896