Can you update to 9.3 on Leopard?
And are you certain you're working in fillable fields? (Are they highlighted to show them as fillable?)
If you see that in the file properties, all it means is that "if" there were form fields, you'd be allowed to fill them in but doesn't mean that they actually exist.
If you are using Reader, you'll get a notice that it contains fields when you open it. If you are using Mac Preview...don't.
And if not, there's no way to change the prefs to make it functional? Even if the security settings indicate filling forms is allowed?
Sent from my iPhone
When the form is authored (created) it has to be created WITH fillable spaces. Otherwise you're asking Adobe Reader to make something available than doesn't exist. Sort of like renting a movie and expecting your DVD player to add characters to the cast.
Which is why I prefer Acrobat Pro over Reader. It has the typewriter tool and you can fill in "unfillable" forms.