In Pythonista 1.3 and earlier, the interactive console and the editor run in different interpreters.
It can happen that a module that is written in the editor has not been saved yet when trying to import it in the console. Saving will generally happen when a script is run or when a different file is opened.
It can also happen that the imported version of the script is outdated (Python does not automatically reload modules that were imported once, they're cached unless they're reloaded manually).
To work around the file not being saved, try running the module from the editor first (or open a different file).
To work around import caching, you could either use the built-in reload function, or use execfile instead of importing the module.