OK, a problem.
Looking at the manual, it says it does play Divx (and then there's a bit about having to register to play the protected Divx stuff) - (it's a Philips BDP3000 player).
I burned the file to a DVD disc as data and it come up "unsupported file format" .
On the support page, it says this under the Divx section:
"Your player can’t play DivX HD, MKV, Q-pel, or GMC formats".
So that answers that. Bummer!
That may possibly apply to other Bluray players as far as HD is concerned. Plays Divx files fine, not Divx HD though.
Shame that wasn't written on the box. You'd think a Bluray HD player would play HD stuff, wouldn't you.

OK, another question. Is it possible to have a lossless avi file to retain the HD?
If I could convert the Divx HD file to a format it can (or may) play, I may still be able to get it in HD form - or is that to simple? I'd really like to watch the files on my 32" TV instead of the PC monitor.
Any suggestions/solutions guys?
I'm just not up to scratch on HD stuff.