I just purchased Etch and when I try to run the License manager, all fields on the GUI are greyed out. This was the case as well on the installer, but I was able to get it installed. I'm running Snow leopard 10.6.8 and logic 9.1.6. I've registered the product on FX's website btw.
When you installed OSX Snow Leopard, did you customize the install in anyway - such as reducing the font set. We've seen this in the past when our installer is unable to find the fonts. You must have one of the following installed: