Hi there
Seeing as no-one else has replied to you, a "PM" is a Personal Message where here on the clean-it-up site you can send such a message to another member and only they can read it and send a personal message back to you.
If you look under anyones post and look to the bottom of their name and information on the screen, there will be a green scroll. Click on it and you can "email" a personal message to that member.
If you look to the top of any page you are on on this site, it will tell you if YOU have any personal messages or not. Place you mouse over this sentance if it says you have a message and click, you will then be able to read them.
Hope you understood the above as I am too tired to read through it and check it!!
Regards
Tim