Nested Objects :: Reuse Some Code In A Different Context To Do A Different Job?

I'm trying to reuse some code in a different context to do a different job.The code to be reused contains hundreds of lines similar to a = new b.c.d(e,f) with different value for e and f.I need to create a new user defined object with the structure b.c.d. I've made numerous attempts along the lines of:

function d (e, f) {
this.e = e;
this.f = f;
}

[code]....

with various permuations of functional declarations.However I get error message "Object expected" or "b.c.d is null or not an object" at the final line of the example.It works with the test line var a = new d("test", "message") but not when I start to build up the expression.How should I define of b.c.d?