Call to a member function on a non-object

I am trying to transfer my opencart shop onto a different server. I have literaly downloaded all the files off the working copy and then uploaded them onto a new server.

I am getting this error now even though it worked perfectly on my other server:

Fatal error: Call to a member function getProducts() on a non-object in /websites/123reg/LinuxPackage22/ca/md/en/camdenpuzzles.com/public_html/catalog/controller/module/cart.php on line 22

Any ideas?

Looks like there may have been a problem when you uploaded your files to the new server. I'd suggest re-uploading them.

I already tried that twice! No idea what specifically might be the problem?

Call to a member function getmanufactureid() on a non-object in D:\xampp\htdocs\opencart_enhancement\admin\controller\common\header.php on line

Why this kind of error occur, getmanufactureid() is a function defined in the model page.

Please help me guys if anybody have any idea....