Why can't I make my object Flexi??

Why does my object not allow me to make it flexible?

The option for this is shaded out in my build menu, and i can not make what i have created flexible!

Some one said I need to use a script - but I have no idea about them, and why do i have to use scripts to do the same thing the building menu is supposed to do?

well not all prims are able to be flexi..

can you be more specific about the build?

As well as only certain prims types supporting flexi, it can only be set prim by prim, and not for a linkset.

It's not scripted - it's a prim option.