Could you ask the person you are wanting to PM to send you a message instead? By this I mean quote the person in the respective topic and ask him/her to PM you for further discussions and also add a note saying that as a new user you cannot create a PM just yet.

Most people here are very understanding and I (personally) could not see anyone objecting to such a request.

@sifo, I think I have lost your second PM from earlier today. Sorry I did not get a chance to read it, could you send it me again