That's not the error I get. I get 5 errors, three of which relate to missing field "unitPrice", one about a non-existing constructor (hint: your Television constructor has 4 parameters but you try to call it with 5), and one about missing method "calculateInventoryTotal()".
Ok. I'll tell you what's wrong with the code in more detail...
If you compile the given code above you'll get total of five errors. Three of them are related to the member variable "unitprice" and one about the wrong constructor used in line 64 and the use of non existing method in line 76.
You have to define a member variable called "unitprice" as you've done with "itemNumber" etc..
As shown below you are using the Television constructor with five argument where the defined constructor only has four.
And you don't have a method named "calculateInventoryTotal()" in the Television class but you try to call that method in line 76.
Fix those issues then it should compile.
Edit: Rob has already given the tips about the code