StoreSearch - warning and CRASH

I just added the URL Encoding code on page 65 (PDF) and the app crashes. Plus, now I am getting a warning too.

fatal error: unexpectedly found nil while unwrapping an Optional value

The warning is on the newly added line and it says: Intitialization of immutable value ‘escapedSearchText’ was never used; consider replacing with …

I figured it out. I forgot to change the other line.