Field Collection module Ajax error I'm utilizing the Field Collection module to allow me to associate objects of one content type (say, Authors) with another content type (say, Books).

When viewing the Edit page for one of my specific Book objects, whenever I try to use the "Add another item" or "Remove" buttons within the Authors section -- which operate via Ajax -- I'm getting an Ajax "403 Forbidden" error on the following URL:

field_collection/ajax


One key piece of information is that this happens with only one specific object; the functionality of those buttons works perfectly fine on the edit pages of other Books.

When I visit the Recent Log Messages page -- admin/reports/dblog -- it displays the following error message:

Notice: Undefined index: form_build_id in ajax_get_form() (line 320 of .../includes/ajax.inc).


I checked though, and the form_build_id does, in fact, appear to be included with the POST data being submitted to field_collection/ajax.

Is it possible that that form_build_id is somehow invalid?

I'm sort of at a loss here. Any thoughts?

UPDATE:

I set up watchdog to log the POST data, and it seems like there's absolutely no data available in $_POST once it hits the field_collection_remove_js function within the Field Collection module code...

Is there a chance I'm hitting some sort of POST length/size limit? The node in reference does, in fact, have a whole bunch of data associated with it.
In case it helps anyone else, I believe I was running into memory limit issues in PHP. Adding the following to my sites/default/settings.php seems to have resolved the issue:

ini_set('memory_limit', '128M');