Got not fixable problem with user registrations

Hi all

got problem with registrations

every time after registrations i see this error

Notice: Undefined index: entry_author in /home/oz2q65zf/public_html/modules/boonex/notifications/classes/BxNtfsTemplate.php on line 159
Notice: Undefined index: entry_author in /home/oz2q65zf/public_html/modules/boonex/notifications/classes/BxNtfsTemplate.php on line 159
Warning: Cannot modify header information - headers already sent by (output started at /home/oz2q65zf/public_html/modules/boonex/notifications/classes/BxNtfsTemplate.php:159) in /home/oz2q65zf/public_html/modules/base/profile/classes/BxBaseModProfileFormsEntryHelper.php on line 203