Php/smarty based website error fixes needed

Ok, this is third time lucky.... i need this error in my website fixing, it happens when i try to empty the shopping cart on the cart page:

Fatal error: Call to a member function GetCart() on a non-object in /hermes/waloraweb018/b1267/moo.organicgrowshopcouk/cart.php on line 38


and this one when i am trying to edit my products in the admin section.

Notice: Undefined index: prods in /hermes/waloraweb018/b1267/moo.organicgrowshopcouk/templates_c/97c13ae6868bbc459509c9f1b968154acd23eecc.file.header.tpl.php on line 176

Notice: Trying to get property of non-object in /hermes/waloraweb018/b1267/moo.organicgrowshopcouk/templates_c/97c13ae6868bbc459509c9f1b968154acd23eecc.file.header.tpl.ph


Also the meta tag information for the products all shows as the same information, can you change this so it shows the information that is in the config file?


and one last thing, i tried making my own template page, and it halfway works, but i don't know how to get the css to work with it, it would be good if you could get this working and tell me how to do it in future.