1.6.11 problem

[mtkarimi]

your the god of php
here is the error
Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 2572109 bytes) in /home/birdsong/domains/birdsong.ir/public_html/inc/plugins/xthreads.php on line 860

i deleted that file, the error still is there even with ctrl + f5

edit #1:
i removed $objserial = serialize($obj); from line 860... but then forum will show but xthread is nothing there
gooood plz i want mybb just for this plugin

edit #2: i called the server and they alocate me more memory
i hope nothing will happen badly
do you have any idea?