Parameter 2 to addanother_form_alter() expected to be a reference, value given in...common.inc on line 2892

In the process of moving my site to a new server with PHP 5.3, I receive an error when uploading files to a node:

Parameter 2 to addanother_form_alter() expected to be a reference, value given in /var/www/html/lawtest/includes/common.inc on line 2892.

I found issues on other modules where removing the & from &$form_state resolves the issue. I don't have a git account, so I can't create a patch, but on my test install, on line 159 of addanother.module, I changed

-'function addanother_form_alter(&$form, &$form_state, $form_id)'
+'function addanother_form_alter(&$form, $form_state, $form_id)'

and the error did not reoccur.