CSS Button Styler will not run "Insert New Button"

I installed Button Styler yesterday but cannot use `Insert New Button'. Every time I try this I get the message "Please save the document within the active site before running CSS button styler". But I already saved the html file before trying to insert a new button.
I thought this was a bug in the software and send a message to WA support. But they reply that I should post this in the forum.
I am using DW CS5. I have tried inserting a new button in the code view panel and in the design view panel, but always get the same message. The menu option `Manage Button Presets' is working fine, it's just the `Insert New Button' option that I cannot get to work. Without it though the add on is useless to me of course.
Who can tell me what I do wrong or if this is a problem with the add on.

I'm sure you have, but have you set up your site definitions fully?

As Daryl says, I think it may have to do with your site definitions…

see the "Defining a Dynamic Site in Dreamweaver" tutorial on the Learning Resources page:
resources.php

Ok, Daryl thanks

Theo