[Zope] classes in external methods

Since Zope's Python Scripts will not allow me to import the csv module, I wrote my own little class within an External Method. My class opens a CSV file and returns a dictionary representation of each line, one at a time. Now Zope pops up an authentication dialog when I try to call my External Method. Is there some way around this? Can someone also explain why Zope does this? I thought an External Methods was a failsafe way to write unrestricted Zope code without going all out and writing a product (which just doesn't make sense in this instance). Nathaniel