Get Selection Size in Pixels

I can't seem to figure this out.

var oCurSelection = activeDocument.selection;
var aSelSize = new Array;
aSelSize = oCurSelection.bounds;

I want to take a selection, make a new document at the selection size, and copy the selection to the new document. However, in the Data Browser, under activeDocument.selection.bounds, I see:

"Error: General Photoshop error occurred. \n. The command \"Get\" is not currently available."

What does this mean? A function I copied from these forums to detect a Selection (detectSelection) says there is a selection. Why can't my code see it?

Thanks,
Matthew Pfluger