Ok, first sorry for my bad english,
Well i got the &%@"# error 601 when i try to pay direct from the moogle station with my credit card, and the error 402 when i try to buy crysta from the
www.secure.square-enix.com site, but what i do was this:
First log in your account in the Moogle Station, select SUBSCRIPTION SERVICES, select pay with Crysta, and cuz i only have 4 Crysta i click on, Add Crysta option, you are gonna be send to the
www.secure.square-enix.com/account/blablabla.com site BUT, in the Payment Method DON'T select the "Credit Card/Debit Card" option, cuz you are gonna get the Error 402, select the "UltimatePay" option and click next, im mexican so in my browser say "10 más opciones", i don't know how say in english, maybe 10 more options, but click in that part, then choose Credit Card option (first one), and now just use the credit card to pay, and thats all, thats the way i was able to purchase crysta and finally, able to play... hope works for you guys!
some screens:
http://imageshack.us/photo/my-images/593/u7wq.jpg/
http://imageshack.us/photo/my-images/24/m9rw.jpg/
http://imageshack.us/photo/my-images/850/q1l1.jpg/
http://imageshack.us/photo/my-images/17/qqkp.jpg/