Only variables should be passed by reference in privatemsg_realname_privatemsg_name_lookup()

Hi,

I am new in Drupal.
I have installed Privatemsg 7.x-1.2 and Realname 7.x-1.0-rc2 modules.
During message sending i have got error info:
Strict warning: Only variables should be passed by reference in privatemsg_realname_privatemsg_name_lookup() (line 10 of C:\xampp\htdocs\lecet3p\sites\all\modules\privatemsg\privatemsg_realname\privatemsg_realname.module).
Message was delivered to user without problems.
Can somebody eliminate just this warning, please?