Luis: The beauty of the new instance system is that none of the engine functions require an object_get_parent().
Regarding your syntax error; if you open the file it mentions and press the syntax check button, it will highlight the place it occurs as well as print the line number and such in the status bar.
This is an implementation of instance_position, returning the first instance AT x,y.
// Copyright Josh Ventura, etc.
int instance_place(int x,int y,int obj)
for (enigma::inst_iter *it = enigma::fetch_inst_iter_by_int(obj); it != NULL; it = it->next)
if (x == ((enigma::object_planar*)it->inst)->x
and y == ((enigma::object_planar*)it->inst)->y)
I've already added it, of course. Look for it in the next revision.