problem with friend request

I'm trying to use the plugin friend request (http://community.elgg.org/pg/plugins/project/728303/developer/vazco/friend-requests-elgg-18) for elgg 1.8, but I pulled the line error file 8 model.php

"'relationship_guid' => elgg_get_logged_in_user_guid (),"

I am using the 1.7.5 version of elgg, but install "vazco_backwards_18" plugin and these methods should work elgg 1.8 plugin the friend request


as I am the site administrator, I put the plugin vazco_backwards_18 first in the list of plugins, as indicated in the description of the plugin, but it did not work, I commented the line but did not work

im trying with another older plugins of "friend request"  and the message is " the requested action (friend/add) was not defined in the system."


thanks

Jp Inteduc