Robin,
The thing you're describing where you die mysteriously from jumping is a bug. Fortunately, Thomas Ward is working on an update patch that fixes that bug even as we speak, and presumably the other one you're talking about as well, where you sometimes jump up, don't land and have to press the Down Arrow. I'm pretty sure that's also a bug, and presumably it's being fixed.
As for getting gems while on a rope, all you really need to do is jump off the rope in the direction of the gem. Try it once, get back on the rope, climb up one more step and try again. All it is is practice.
As for avoiding monsters, the only way to do this is to jump over them. Timing is going to be your friend, as well as having a healing potion handy for the snakes and spiders. Potions not only heal your injuries but also cure snake and spider poison, otherwise your health will decrease by ten percent every few seconds. The best way is to make sure the monster is close enough to hear and identify but not really loud. Angela seems to have good jumping ability, so jumping and pressing Right once when the monster's relatively close tends to put you out of harm's way. When the patch is available it should correct the Death Jumping bug as well as a good many others. Then perhaps we can start seeing later temples and other game features and things. If you want, you can join the Audyssey Gamers' List at www.audyssey.org. There's a link to let you join a mailing list where you can get help for just about any audio game and discuss future games. Thomas Ward from USA Games posts to that list quite frequently and it's him that told us all about the new patch for Monty. I'm on the list so you'll probably see posts from me. But anyway I hope I've managed to answer your questions. I myself was bothered by the bugs but you have to remember this is the Alpha stage, so bugs there will be. Anyway, hope I've managed to clarify at least some of your questions. I'm hear to help and plan on posting a walkthrough for those that are really stuck.
But wait, what's that? A transport! Saved am I! Hark, over here! Hey nonny non, please help!