Hi monbron,
The link on Private Moon's site leads to The Adventure Shop, here:
Yoomurjak's Ring There has been some discussion regarding The Adventure Shop recently. They haven't updated their site with any new games in quite a while, and there appears to be an issue with passing royalties to at least one developer, so they are no longer affiliated with GB. But the game is still available from them at the present time.
If it's available elsewhere, I hope someone will post to let us know.