! Library feature is empty

I have been working my way through my Weldments tutorial and after editing a piece of 2x2 angle .SLDLFP to make a 2x3 angle and saving it in my newly created folder as a 2x3 angle.SLDLFP I then navigate my way through the "insert structural member" command and find my newly created library feature.

However after selecting the sketch entities that I want to define the structural member and selecting OK I get the screen report "!library feature is empty"

As a check I open my new library feature and for reference open the original 2x2 angle library feature. They look the same (except for my update).

Anyone any idea what may be wrong?

I am using Vista on this computer

Thanks in anticipation
Cameron