I have had issues myself porting to other platforms, mainly because I'm unfamiliar with them, so I'm not going to be much help there! Sorry!
I believe some exports work better than others, and some *do* work, as Lantern's author Evan Wright uses it as a teaching aid in his school, and they've made physical copies of games authored in his classroom for systems other than the Spectrum.
It may be worth writing to him via the email on the Lantern site and asking! I'm sure you'd get an educational response!
Hope that helps! :)
QS =D