Are you sure your translation.ts file is readable by the web server?
Did you check if the translation is really done (check it with linguist)?
What tells you the Debug? Do you have some "Warning: ezi18n" output? Did you try with another language (spanish for example)?
I checked thoroughly the ezwebin translation file (the one supplied with ezwebin in eZ installation!!), and it had an error I couldn't define. o_O It just didn't work, despite proper coding, etc.
However, I created another translation based on untranslated .ts file, and now it seems to work well. It cost me lots of time, but anyway. As I finish it, I might send it to eZ Crew to implement.