obj.setDataProperty gives me 'object doesn't support this property or method.'

Aside from a few issues, my grid seems to be working very well - I'm using paging, multi-selections, row higlighting, sorting, onclick methods, context menus, etc.

However, when I call obj.setDataProperty or obj.getTemplate("top/item", i).element().offsetWidth, I get errors.

obj.setDataProperty gives me 'object doesn't support this property or method.'

obj.getTemplate("top/item", i).element() returns undefined, thus trying to access the offsetWidth property throws an error.

Are these methods that are only available at a certain time? I've seen these used many times in the forum, and have used both of these myself in a few demos, but for some reason they do not work in my production code (which I'm sorry I cannot post.)

Does anyone have any ideas? HELP!!!