Try making the first letter of your password a lowercase and keep them all lowercases. If need be, if your password is short(like 6letters), then just type your password twice and it should allow you to become a member of paypal.
If you have a credit card, you do not need an account with paypal.
If you are using a bankaccount to combine with paypal, you have to wait 3 to 5 business days while they depoist two small amounts into your bank account and when you get your bank statement, you then go to your paypal account and enter the two amounts that they depoisted and then you are a verifed member of paypal and can send money out to others. But like I said, if you have a credit card, you don't need to register to use paypal, just enter your CC info on the page.