Joomla fix required (contact forms)

We have a Joomla website which is running on a particularly old version of Joomla (1.5 I think) The contact forms on it have stopped working about a week ago, we made no changes to the website and our hosting company confirms that they have made no changes to the Linux platform. So it's a puzzle. The forms have until recently worked perfectly and we have no idea why they have stopped working. The forms themselves are not particularly simple, I understand they are modules but use code which has been written in to one of the Joomla files. Our site uses two contact forms, one in the side bar and one at the foot of all pages. We also use Joomfish to translate so those two contact forms are in German and English. We cannot readily see the code which includes the email addresses, but German forms go to one address and English forms go to another. Please only bid if you are a Joomla expert and can get to the bottom of this problem quickly and without breaking something else on our website. Freelancers that show no indication that they have read this project description and are just sending us a cut and paste message with a portfolio will probably be ignored. All the best