Oscommerce Errors to be Fixed

I have few errors appearing on my Oscommerce site. First of all would like to inform you that I recently changed my hosting servers. I restored my whole site to the new server and I am getting a new error below: 1) Error in Admin Panel: All headers in the Admin is appearing like "TABLE_HEADING_CONFIGURATION_TITLE"...it is not being converted to the language. I have attached a printscreen for your reference. When I click "Catalog" tab, it shows 'HTTP 500 Internal Server Error'. I think the "[login to view URL]" file maybe configured incorrectly. So please check that file as well. Some tabs, when I click, it shows this error: Error! Unable to determine the page link! Function used: tep_href_link('', '', 'NONSSL') _______________________________________________________________ In the catalog website, under My Account - "My Orders" - "View the Orders I have Made" - "View"...error appears when I click f you would like to view / print a pdf version of this invoice, click here. Error: FPDF error: Some data has already been output, can't send PDF file DOWNLOADED PDF Customer Invoice + Email Attachment Module. _______________________________________________________________ I want to change the welcome email when customer registers an account. It is in text but I want to be in html to add in logos and change the font etc. Also welcome email goes to junk...want in to go to inbox if possible. ______________________________________________________________ Downloaded Points and Rewards Module... I set to auto credit points after purchase. But I realised an error. If I check the option "Pay by Paypal" and when I reached PayPal page, I clicked the back button but then I saw that the points were already added to the account. Which means even before completing the Paypal Transaction, points were already auto credited to the account. I have made the points addition to manual now but I want a fix for this issue.