The first mistake you have made is using Late Binding.
There is no value to using late binding in this instance. The only advantage to late binding is version independence, i.e. you can write code in a newer version and it will theoretically work in an older one. But that advantage is lost unless you also use late binding for the host application code as Office is usually installed as a package. It is better to use early binding when working with other Office applications and reserve late binding for other commonly used libraries, e.g. ADO or XML.

By adding a reference to the Excel library (Tools | References) and declaring the object variables with their correct types (eg. Dim chartObj As xl.Chart) you get the benefit of IntelliSense.

Instead of What you need is When pasted this will give you a linked chart but the link can be broken by adding something like