Of course, that might NOT be the problem too. Using a higher wattage iron increases the probability of frying a componenet, but doesnt guarentee it. I used a 30, no problems, just had to be aware of how close to the chips I was getting.
Take a look at the chips around where you soldered. Do they look burned? Check for anywhere near where you soldered that you might be bridging two traces. I would think that would be more likely than you burning out a chip by using a hotter iron.