After some private message with Alfredo we found the issue.
For those wou are having the same problem.
Make sure that when you use the web package by inheriting <inherits name="com.ekambi.gwt.web.flex.FlexWeb" />
and not <inherits name="com.ekambi.gwt.air.core.Gwt4Air" /> or <inherits name="com.ekambi.gwt.air.flx.Flex" />
The two last are for the gwt4air AIR package. Meaning only for Adobe AIR application.
Cheers
Alain