Nested layers won't convert to table

I have nested layers on my page and when I try to convert layers to table, I get an error message saying that I can't because it the resulting page wouldn't be compatible with 3.0 browsers.

1. Does anyone still use 3.0 browsers anymore? Is this really an issue I need to worry about in the present day and age?

2. If I don't care about making the page compatible with 3.0 browsers, how do I get Dreamweaver not to care either, and convert the layers to table?

Thanks!

Sensa