Why doesn't a 3gp file play on ipad2?

Probably lacking a codec. Try mpegstreamclip and see if it can convert it to a mp4 or m4v for you. It's freeware

Handbrake might also work, but I'm not sure.Format Factory would but it's a PC only piece of software.

3gp is a av container, not a codec.

It can contain different video codecs.

Apparently, the one used is not natively played by the iPad.

You can download an alternate player(I like avplayerhd) on the iPad and see if you can play it or download it to a computer and convert it.

I like handbrake for that.

bad phrasology on my part

thanks 🙂