Magento store - open to bidding

ONLY EXPERT MAGENTO ESPECIALISTS We are looking for an expert in magento and linux. Today, we are running our e-commerce store at amazon aws centos with nginx and php-fpm. We need to fix couple of problems with our store. 1) First of all, we only have production website, so you MUST be very very careful, creating backup of everything before otherwise we are going to have a lots of costs and problems. 2) For some reason, our inventory in magento is going negative , sometimes i see products with -4 , some -2 and mostly -1 , i did fixed at the admin configuration, but what i believe is that for some reason, some client that had put the product on the cart, he log off, and then log in, when he log in, his products still on his cart, so he can buy it. i BELIEVE this is the problem, but i am not sure. 3. The index - Product attribute is not indexing, it give an error. 4. Need to install cron at the server 5. Need to create an automaticly backup, when i try to do it on the config, it runs the thing, but doesnt create the file. i believe it might be permission folder. 6. When we are trying to create a order at the administration painel, if give an error - FATAL ERROR: CALL TO A MEMBER FUNCTION getBackUrl() on a non-object in …./[login to view URL] on line 287 7- When we type the zipcode at the onepagecheckout it is not loading the address, so the shipping cost is not calculating, it was working and always had before, for some reason is not anymore. 8- We are trying to set up the ecomerce to sell by credit card automaticly and is given this error. Fatal error: Class 'JavaScriptPacker' not found in /app/code/local/Cerebrum/Telencephalon/Helper/[login to view URL] on line 1357 9- create a copy of this website and database for test website . 10 - install banner module that we have ngw 11 - install facebook login at the store