Erm... are you guys sure "suttoko" is supposed to mean something?
"Suttokodokkoi" is defined by WWWJDIC as "idiot; fool; idiocy; stupidity".
According to the entry in the Japanese Slang Dictionary, "Suttokodokkoi" was originally a nonsense phrase used in festival music, a word to scorn or insult a target. It was often used when someone of lower status made a mistake, along the same lines as "bakayarou". There are various opinions on the word's derivation, though they share the idea that it's a portmanteau of "suttoko" and "dokkoi". One theory holds that "suttoko" means "naked body" and "dokkoi" is a variant of "doko he" or "where [are you headed]", and that it thus came from being used to chew out someone wandering around practically naked.
However, since the context here has nothing to do with nudity (and that part's just one theory, anyway), I went with it being an abbreviation of "suttodokkoi", and thus, "fool".