That doesn't make much sense why it wouldn't work with any type of amp. Your amp should accept whatever signal is being sent to it. I could maybe see a pedal not having the full effect if this guy's amp was set to some kind of DSP mode that maybe included an "auto wah". When you get it, try it with all effects disabled and see if it works, then engage each effect one at a time and see if you notice any ill effects. I have a little SS orange practice amp, a couple of old champs, and had a hot rod deluxe, and the crybaby works fine with all of them. Worst case, return it. Also, you might want to contact the place where you bought the amp or Line 6 directly and ask them about it. Good luck

FYI I've got a friend with a weeping demon and he swears by it!!! The stuff he plays uses a lot of wah and he says this is the best one he's had by far.