Mellissa,
Glad you were able to solve your issue. The solution you found is for when you are creating your own web mapping application with ArcGIS Server Manager. 
For those that want to enable pop-ups in their web maps in ArcGIS.com, it's now available. Right-click a layer to reveal a context menu and enable pop-ups. If you don't see this option, you're not yet accessing the actual layer inside the service. Click on the layer to expand it and reveal its sub-layers.
Thanks,
Mike