about 1,
is it possible that your native method is executed before the lscommons.js and lspushpage.js files are included on the page? Maybe a little digging with firebug could help you find why the PushPage object is missing.

about 2,
probably the problem is in your setDomain call that shouldn't be used with "localhost":

you may use null if pages are served by Lightstreamer server, but that's not your case, so you should use an actual domain. If your pc has not a host name, you can modify your hosts file to mimic a host name.

e.g.: if in your hosts file you put
Code:
127.0.0.1    me.adomain.com
then your setDomain will be

and your setLSHost



Btw if you find the solution on a GWT forum we will be grateful if you report here a link to it.
cheers.