Lexical variables ( i.e. ones declared with my ) can't be used outside their scope. Therefore, the quickest way to get this code to run is to make your variable global (i.e. a "package variable") using either our or use vars.

However, globals should avoided when possible, so this might not be the best long term approach. With a little more about what you're trying to do, its probably possible get rid of the globals all together.

-Blake