Possible Game Defect

I recently downloaded Chrono Trigger to replay on my emulator. For some reason, towards the end of the game, I am unable to deal any damage to Rust Tyrano using any character's (other than Crono) attack or spell. Multiple FAQs and walkthroughs I've read online say that you can damage Rust Tyrano using anybody.

Do I need to revive Crono first in order to defeat Rust Tyrano (I forget the first time I beat him years ago)? Or is there just a defect with the ROM I downloaded? Has anyone else encountered this problem (not being able to hit him for any damage)?

Any help would be appreciated.

Maybe you shouldn't play a crappy emulator and just buy the game. Sorry, I just don't like emulators that much, they tend to suck.

I am pretty sure you can kill it with anyone though.

I do own the game. It's at home, and I'm away at school right now, and I felt like playing it.

But you're right, it could just be that the emulator sucks.

Try getting another ROM and loading it up with a savestate or savegame. Most problems like this are caused by really, really crappy low-end interleaved ROMs.