OK, I'm trying to follow everything you just said. It sounds like you just might be talking about some yeast on the top of the beer. I can't be sure, but I see this a lot in my beer and used to worry that it was mold as well.
Did you take pictures of the mold-like substance? Can you post them here for us to see?
Also, if the beer tastes good (Even after the bottle bomb), you're beer is probably fine.
If you continue to have bottle bombs, I'd suggest throwing your beer bottles into the fridge to stop the bottle conditioning.
"There is no strong beer, only weak men"
"Pretty women make us BUY beer, ugly women make us DRINK beer" - Al Bundy
"Give a man a beer, he'll drink for a day. Teach a man to brew, he'll be drunk for the rest of his life."
Primary: Viking Metal, Berliner Weisse
Kegged: Oaked English Mild, Modus Hoperandi
Notable Empties: Oaked Black IIPA, BBK I, Red IIPA, Burning Bush, Apophis "The Destroyer", Vanilla Porter
On-Deck: Hobbit Ale, The Titan BW, Ale of Olympus