i've been trying to buy the rest of this years i bonds.. i keep getting error 500 or 404 , which says that there may be a problem because of a bookmark! i don't know how to bookmark!

worked fine last mo , but i had to get a credit limit raised to get the max. now it won't let me buy!
i'm using ibook w/os 9. have no idea what browser i have. any one have an idea. thanks