This looks really safe, Beth! Bob's right - there's very little caffeine in cocoa. Here's something Linz pointed out a while back:
"The caffeine in cocoa is carried in the fat so cocoa powder has very little caffeine in it that can get into your bloodstream. This is why we use cocoa powder and NOT bitter chocolate (fat therefore caffeine)." Caffeine in Cocoa Powder
I also read that for people who tend to get migraines, it's mainly a chemical called phenylethylamine, not caffeine, in chocolate that triggers headaches. Like Bob said, it's the fat content in certain chocolate products that triggers IBS symptoms.