Correct me if I'm wrong, but I suppose you want a default table inside of your rich text box everytime someone creates a page based on your page layout?
This page content rich text box is actually a field that's part of your content type. It's not connected to your page layout, so I'm not sure you can add default data into it.
I see three possible solutions.
You add your default table through a workflow that automatically injects the table inside of the field.
You don't use the rich text box and create a webpart zone. This webpart zone can contain a content editor web part that by default already has a table inside of it. (This is what I would do, but be aware of limitations concerning putting data in webparts as opposed to page fields)
This is what I do when I want to create a page with some default content in it.
- Edit your page layout and add the webpart zone to where you want the default content to appear
- Create a page based on this page layout and edit it
- Add the content editor webpart to the webpart zone
- Edit this webpart so it contains the table you want with the correct formatting so it's at least visible when people create a new page based on the page layout. Do this untill you're satisfied with the result
- Open SharePoint designer and go to the library containing the page you just created and customize
- Right click it and select "Detach from Page Layout"
- Right click it again and select "Edit File in advanced mode"
- Go to your webpart zone, copy the webpart and put it in your PageLayout under the ZoneTemplate element inside of your webpart zone.
It should look like this:
<ZoneTemplate>INSERT YOUR WEBPART HERE</ZoneTemplate>
- Now, everytime someone creates a page based on your page layout, the table should be present.