hi I don't know when it got broken, maybe tcl/tk 8.5 has changed ?
this line in pd.tk
bind $name.c <Alt-Key> {pdtk_canvas_altkey %W %K %A}
should be something like
if {$pd_nt == 2} { bind $name.c <Option-Key> {pdtk_canvas_altkey %W %K %A} } else{ bind $name.c <Alt-Key> {pdtk_canvas_altkey %W %K %A} }
... gerard