i can't join some PTC site. Why?

Are you having your own computer? If you are in a place where other people also uses this computer having the same IP address this might cause this problem. Many sites does not allow two accounts with the same IP address. So if someone else have signed up on this computer before that might cause the problems. While I am at it I want to tell you, if you are interested, to have a look at my blog. This last week I have been paid by five different sites, so if you want to join more sites that pay, have a look there!