I'm using EC v3.4 on Drupal 5.7. When I go to edit a single item from a transaction, I get the following error:

warning: preg_match() expects parameter 2 to be string, array given in /home/www/celston/includes/bootstrap.inc on line 670.

I've traced this to the function store_transaction_edit_items_form in store/store.module.

  $form['data'] = array(
    '#type' => 'hidden',
    '#value' => $p->data,
  );

The value of $p->data is an array and is eventually run through check_plain and fails. Should it be serialized beforehand? If so, you'd have to take that into account on the receiving end when it's eventually run through store_transaction_save_product.

Since the contents of "data" don't make it into the form, it gets lost. I'm hoping to write a module that alters this form for the purpose of exchanges and this is preventing me from moving forward. Any help or suggestions are welcome.