Attachment Problem

When I go to attach something in my email account, it will not let me attach any documents from pages. Instead of appearing in black, al docs from pages are light grey and cannot be clicked on. Can anyone help with this?
THanks!
BTW i have a macbook running Leopard and this is in a yahoo! mail account

You may have to set up a Mail account to handle attachments from iWork as the program may only recognize MS Office documents.

Here is a link to a tutorial on Yahoo Mail:-

http://help.yahoo.com/tutorials/mmail/mmail/mm_compose5.html