Adobe Acrobat XI Pro Installation and Registration Online

Hi Everyone,

I bought three (3) Adobe Acrobat XI Pro for windows. I installed it into my three (3) computers I choose to input my serial number (because I have one), after I completed installing it I was prompted to register it online. But there was a error saying that I don't have a Internet Connection (please see the image below) it's a weird thing because I do have one. 

Now, my questions are :

1. How can I solve the problem regarding the Internet Connection thing? My clock and and time zone are correct.

2. Is there an alternate way to register my software online?

3. I want to un-install my Adobe Acrobat to my previous computer and install it to my new computer, will the Serial Number be counted? Being said that I installed and input the serial number into my three computers.

I'm afraid that if I install and input serial number to my new computer, the serial number will not work because I used it three times.

Please help me with this matter. Thank you in Advance!