Chrissy,
I have Free form Window and have used it several times in AC 10
and I do not get any errors. According to the author this
object was saved in AC 8 and should work in AC 8, 9, 10, and 11.
Is this the first time you have tried to use this object ?
Do you get this error in the preview window before you
insert an instance in a wall or do you get the error after
you have edited it's parameters either in the settings dialog
or in the 3D or Section/Elevation window ?
Have you tried drawing a wall in a new AC project, inserting
an instance of the object without editing any parameters
and see if you get the error ?
I am asking these questions because the type of error you are getting
is a GDL syntax type error and should have nothing to do with the
AC version you are using and therefor, as sometimes happens,
the error is in error and something else is wrong often having to do
with parameter settings.
Peter Devlin