I'm no expect: I have just begun experimenting with cuttings as well. But I can tell you that, yes, not watering the rooting medium is the problem. The leaves will hold water, but the plants get their water through their roots. You have to keep the leaves wet while the plant develops roots because it is not drinking enough water through the small end of the cutting alone. But you also must keep the soil moist to allow the cutting to begin to drink and develop roots.

Also: I've been told perlite alone is not recommended, but to try a 50/50 mix of perlite and peat moss OR a 33/33/33 mix of perlite, peat moss, and sand. Each type of soil has it's advantages. The perlite helps the soil from becoming too compact for the cutting to root, the peat moss holds water and also doesn't easily compact, and the sand maintains water (though, sand alone will quickly compact quite a bit).

You should keep your soil moist, but not sopping. If you don't have many plants you can save plastic jugs from juice or water (as long as they are clear). Plant your cuttings in pots small enough to fit under the jugs (cut the narrow part off the jug) and you have a small green house. If, like me, you are attempting many cuttings you can use clear plastic and build boxes to plant in and cover them.

Lastly, work indoors. Clear a space out in a bright room, but do not place your cuttings in direct sunlight. It's just cooler indoors and they will not dry out as quickly. Obviously the best choice is a green house, but there are ways around it. I would recommend calling the first set of cuttings a loss and beginning again. It's probably late enough in the season that you are working with semi soft wood so expect the cuttings to take 6 weeks to 4 months to root.

Good luck!

You do need to moisten the perlite. I have rooted Abelia cuttings successfully in moistened perlite alone. Other combos as greenamanda mentioned work well also. I am no expert either, just wanted to post mostly to mention you need to open the ziplock a little, or at least a short time each day. It lets the plant breath, and also keeps it from getting too hot.

Don't give up. It took a few tries before I had my first success, but when it worked I was SO HAPPY. So keep trying. It is one of the most rewarding things in gardening (my opinion). My husband thinks I buy new plants now just so I can try propagating them :~).

I set up my clear tote prop chamber yesterday with about 50/50 perlite/peat moss and moistened it really well. I put half a 2 liter Mt dew bottle in the middle filled with water. Then applied the root hormone to some Yew bush cuttings and some tall version of sedum and threw in some green wood cuttings of my concorde grape vine because that's all I had here at my house.

In the original easy prop chamber thread I read some said to prop open the tote and some said they didn't and had no problem. I might prop it open a little bit just to be safe.

This time of year for semi soft wood cuttings I have a 4ftX12ft misting bed outside in the shade.
I mist 12 seconds every 10 minutes.
The cuttings get about a hour and a half of sun each day and the rest is shade.
So far this year I have rooted 200 crepe myrtle, 100 Indian Hawthorne, and have 200 each of Bloodgood and Green Japanese Maples rooting now and fixing to stick around 500 more of each in Humidity Chambers this Tuesday.
I build my misting beds 6 inches deep and put 2 inches of small gravel in the bottom to aid in drainage and put the rest in Course Sand like you'd use in Concrete not masonary sand which is too fine and will hold water.