Change line 427 of award.php from
Code:
WHERE username = '". $vbulletin->GPC['awardusername'] ."'
to
Code:
WHERE username = '". mysql_real_escape_string( $vbulletin->GPC['awardusername'] ) ."'
Repeat for line 556, and the bug should disappear. If you're paranoid, repeat for every other variable used in an SQL query in the file, although in principle it looks okay.
Is this extension maintained? Are the maintainers on vacation or something, perhaps?