How to get form submition block

how to get the form add simple reservation submition in block placed.
I have installed 6.x.1.1 simple reservation module.
I have tried to call using a snippet of php and placed on block like this:

<?php print simplereservation_reservation_add(); ?>

form add reservation submition display on block, but failed if submited.
error report "Fatal error: Call to undefined function _trigger_get_hook_aids() in /home/*user*/public_html/sites/all/modules/simple_reservation/simplereservation.module on line 89"

Who is can advice?