>I can't figure out what the ";" is for in the second button.
>Or what the "IV" portion of the PICTURE is doing.

@ = PICTURE contains a FUNCTION code
* = the current line denotes an input control other than a text field
I = this is an invisible button
V = that is aligned vertical
; = separates the captions between individual buttons. In your case, the buttons have a no caption.

>The FUNCTION in the last two don't seem to match the codes in the help. What would "pupdhe" and "pdae" be for?

Those are variables.