Re: can not pay with credit card now, why?
Sorry to head you are having a billing issue.
Try to use different browsers, try Google Chrome or Mozilla, delete cache and cookies of your browser. I hope this helps. If that still doesn't work it is probably best to give the billing department at AdWords a call.
The link below will give you their support number. Just use the drop down to choose the country you are in. http://support.google.com/adwords/answer/1385067?hl=en
Stefan T Martinez
-- Not an AdWords expert, just a student eager to learn more...