When an EXT plugin is deployed the classes inside ext-<plugin-name>-ext-service.jar
can be accessed by any plugin since it this goes in the global class-path (/tomcat/lib/ext
for tomcat) just like portal-service.jar
of liferay.
But the classes inside ext-<plugin-name>-ext-impl.jar
can only be accessed by EXT and hook JSPs (if any), since it is similar to portal-impl.jar
since this resides in \tomcat\webapps\ROOT\WEB-INF\lib
which is in the portal class-path.
So if you are accessing classes inside ext-impl.jar
, which seems to be the case then I am sorry to say but you are out of luck.
May be some work around can be found if you can provide more information.