i think he means cause your missing a : at the end. although it still seems to work without it. i always thought it was necessary.
Instead of
if ($2 isin AquariusPiscesAriesTaurusGeminiCancerLeoVirgoLibraScorpioSagittariusCapricorn) {
i\'d suggest using $istok(Aquarius|pisces|...,$2,124) or something, the way it is now will trigger on bogus things like !horoscope a or !horoscope nican lol