Family Creation error on loading

[cjharley1450642179]

Hi Folks

I have attached a family of a lintel but when I load it into a project I get errors, need help. going out of my mind lol
my goal is to make nested windows that include lintels, Sills etc..

But I keep hitting this brick wall, I asked my local Autodesk supplier for a 1 day course on families and nested families, they were looking £2100 for a 1 day course.

all help would be greatly appreciated

[cjharley1450642179]

I have re-created the above but used the window family to begin with and the lintel worked,