You should be able to send an email to the person. When you pull up the person's profile, you are given the option of sending a PM or an email. Click on the email link.
You only need to contribute a bit more and the restriction on PMs will be lifted. The reason we have it is to prevent folks registering to spam others. (You want a Russian wife? I have points to sell. etc)
We are happy to have you here and welcome you into our community.