What's up Green - So sorry nobody's helping you out yet man... Please don't get your hopes up, though - I'm just a lame ass newb. While you're waiting for some serious advice, however: Get some H202 in your res NOW! What the heck are you waiting for bud? I'm assuming you've ordered some "real" H202, but in the meantime, just grab some 3% from a local store! I'm using about a 1/2 ounce per gal. at each res change, and replacing 25% daily. My plants seem to love it. That amount is for relatively healthy plants though, and a clean res. Do a search here, and I'm sure you'll find some recommendations for active root rot and algae.
Speaking of algae - is your res completely light proof? Don't assume, like my dumb ass did. Also, the brown on your roots, even with my limited experience, sounds like root rot. Make sure your res is well aerated; add more airstones, or a better air pump. AND make sure your tank temp is in a good range. I believe they say, especially with any hint of root disease and "crap in your water", to try to keep the res at a nice LOW temp... 68 deg, at least until you resolve your problems. That will still allow for healthy growth, but won't be warm enough for anything that's NOT supposed to be there to grow..!
Good luck man, hope you work it out! And don't be discouraged, bro, SOMEONE will help you - just be patient! The people here are very cool, and very helpful. One thing, though: you need to give some more specifics on your setup if you expect people to really help you.
OH - Forgot about the mold! Wow, I'm so sorry dude! Are you sure it's mold, and not just mineral salt residue? I had the same problem, with white stuff all over my rockwool. Got lucky, I suppose, as it wasn't mold. What's your humidity been like? Your room, and setup clean and relatively sterile? Again, post more specifics, and someone WILL help you figure it out. PEACE