problem with newsletter on OScommerce

Hi we have a problem with our newsletter on our swedish webshop. When we send out a newsletter to our about 2200 costumers the site stops to send out orderstatus to us and the customers that makes orders. This stops for about 24-36 hours. This is a big problem because then the new orders cannot be payed and we have to send them out manually with paymentinstructions and copy/paste all information. and it takes a long time. We need to get this fixed fast. there is also a error message when we after we press send on the newsletter. "page cannot be shown" or something so im not really sure that it reaches all customers The site is hosted on [login to view URL] Please bid if you know a sollution. This cannot be to hard and we cannot afford to pay more than $30 Best regards Mats