Hey there. It's been a while. :) We're migrating our massive laszlo application to SWF9. We do several javascript calls in our app, and I was having issues calling lz.Browser.loadJS() several times in a row. Basically, not all the calls were making it through to the browser's javascript.
Anyway, after much trial and error, I discovered that as3 has ExternalInterface.call() for this purpose, and sure enough, using this native call directly works. So.... not sure if this is the right place to suggest this, but you might consider updating loadJS() in kernel/swf9/LzBrowserKernel.lzs with ExternalInterface.call(). -chris