If you are having some trouble with Joomla`s Pagenavigation plugin not working on your Joomla 2.5 site it is most likely your Template that has not been update. The best to do would be to wait for an updated version of your template to use on Joomla 2.5 or you could update your template as shown below.
Navigate to and open:
Find these lines:
Add these lines after the lines mentioned above:
Then find this line on the bottom of the file:
<?php echo $this->item->text; ?>
Add these lines above that line:
Then find this line at the bottom of the file:
<?php echo $this->item->event->afterDisplayContent; ?>
Check to make sure there are no other lines around it talking about pagenavigation or pagination.
Then add these line above the afterDisplayContent line.
You should now be able to see the navigation and you should be able to set it to display on top or below the content.