A couple people on IMDB and Amazon mention having the promo disc. Try contacting them. However, I wouldn't get my hopes up too much. That's the only mention of it having a 5.1 track anywhere on the net. Considering the following this film has among animators, that disc would be quite a prize if it had 5.1 audio. But there's no mention of it anywhere but on that one page. Oh yeah, except for one listing for a VHS copy that stated it had 5.1 surround. Heh.

It seems possible the guy didn't know what he was talking about. Sigh.

Edit:

Son of a bitch...look at what I found:
Clicky clicky

It's a cover scan of the Canadian promo release.

Look at the small text in the bottom left corner. End of the second through the third line reads:
This DVD is authorized for sale in Canada. Distributed by Alliance Atlantis & Kellogg Canada. Plus it has only the Canadian G rating logo, and it has the 2001 printing date.

And...it only has a Dolby Digital logo, with no mention of 5.1 audio. Christ, just look at the cover...it screams "cheapo". Plus it was printed by Alliance Atlantis. AA is one of the companies that, among other things, prints the cheap ass DVDs that sell in Target and Wal-Mart for a couple bucks. They do some slightly higher end stuff, but they're pretty low rent.

Plus, just think about it. At what point would a 5.1 track been mixed? Dolby 5.1 didn't come around til the early 90s, and they did a rush job to get this thing into theaters in '93, trying to minimize the losses. Would they really spent the money to utilize (what was at the time) a state of the art technology?

I hate to be the bearer of bad news, but I think that's it. No 5.1 track.