WHMCS EDITS / ERROR Fixes

Hi there, I have a number of errors on my install of WHMCS that need investigating. Any changes you make to the site need to stand up to the WHMCS install being upgraded over time. IE that should not be overwritten by a new install and your work should be in overrides if needed. I have two errors right now that need sorting: 1: In the admin area of the site, when I click on the "View PDF" of an invoice, the system takes me to the login screen on the front end. It should just show e the PDF of the invoice in a new browser window. 2: On a new order from the front end, when the user goes to make payment by any payment provider (currently Direct Debit is defaulted) the user is presented with a WHITE SCREEN. However, if the user logs in to just pay an invoice, it goes through the checkout process fine. It only occurs on settin gup new orders in the front end. Needless to say, I have had a lot of abandoned orders because of this. I have other work that I wish to be done on my WHMCS install and the right candidate will likely get more work from me if you are proficient quick and detailed in your work ethic. I am keen to change up the front end of the site as I think it is a bit stuffy and could do with a new 'Flat Responsive Design' something akin to [login to view URL] (although this is for joomla.) This is not something for THISA project, but I would be interested in your thoughts about developing a template similar to this (responsively) and with the same animations, for WHMCS) Please respond with 'surf' in your message so I know you have read this item fully. Also please note you are bidding for the tasks listed in POINTS 1&2 only. But feel free to leave me a message about your thoughts on the template work for another time.