How to reference a subform from a button inside the subform

I'm just wondering if a script I am using to make a subform invisible is really right or if there is a better way to script the action or something I need to add to it to make it work better.

I have a subform named "InstructionDialog1SF" and within this subform there are three fields, two static text objects named "OverviewCol1", "OverviewCol2", and a button named "Close". In the "Close" button I have this script,

InstructionDialog1SF.presence = "invisible";

which makes the "InstructionDialog1SF" become invisible when clicked. It works on my computer when I open it in Preview and when I open the form in Acrobat 8 Professional. I sent the form to a guy in the Japanese office and he says the "Close" button doesn't seem to work. He says the "Close" button worked fine in Adobe Reader 9 and but when he opened the form in Acrobat 8 Professional he says the "Close" button doesn't work.

I saved the form as an Acrobat 8 (Dynamic) XML Form.