Hi
When you are in Rootschat look at the top of the screen and you should see the words
Welcome back, Lucy2, you have nnn messages, n are new (n is a number)
Select Messages and it should open in your Inbox and you should now be able to read them.
Above each message you should see the a Reply button.
I suspect that it is not that you can't use the PM system but that your computer security is not allowing you to open a website from a link on an email.
Andy