PHP SMTP Problems and Wordpress Problem needs to be fixed - Plugin conflicting with WP theme

Problem #1 --- I have a responsive WordPress theme that works fine. The problem is the shopping cart plugin. It is not conforming to my theme layout. The product page is not allowing the proper header to show and is attempting to show the slider. It also is not adding the correct sidebar. The theme allows for different sidebars and different sliders (or turn them off which is waht I want). The WP ecommerce plugin is not acting well with my theme. I need this fixed right now. I will tell interested bidders the website so they can see for themselves what it is doing. Problem #2 --- I have two websites I have moved to a new server on NameCheap. When someone applies to be a member (Site #1) or post a new job (Site #2) they should be sent a validation email and then I should receive an email there is a new member or a new job order waiting. This is not happening. I do see error emails bouncing to my AtMail box for the cpanel mail: This is what they say: Subject: Mail failure - rejected by local scanning code. A message that you sent was rejected by the local scanning code that checks incoming messages on this system. The following error was given: "Relaying not permitted" NameCheap Technical support said I needed to have SMTP included on my php files. If you know what they are talking about, then you should be able to fix this. MAX I WILL PAY FOR THIS PROJECT IS $15 US - if you bid higher you are wasting your time. This is an easy fix for someone who knows what they are doing. You must have Wordpress and PHP [login to view URL] I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15MAX I WILL PAY FOR THIS PROJECT IS $15