I would think that if you started with dried herbs and a clean jar, a 40% alcohol would be more than adequate to keep mold from forming. Generally speaking, you want the final tincture to be above 35% or so for preservation purposes. The green film could perhaps have been small particles of leaf powder? The final red color looks right for a SJW tincture to me.
As for fresh vs dried tincture, while I agree that in general fresh herbs make for a more potent tincture, I've made plenty of tinctures from dried herbs that worked great. If that's what you have access to, then go for it! And one very important thing to remember about making tinctures from fresh herbs: the water in the plant itself is going to effect the final alcohol content of the tincture, so you can't safely make fresh tinctures from 80 proof vodka. Most herbalists start with everclear or other high-proof alcohol, and do some math to figure out how much they need to dilute it to get the correct final proof. So for beginners, tinctures from dried herbs may be the best way to go.