The generated JS is not supposed to contain a p._path assignment any more. You only set p._path when you want to override the request path on an individual proxy. When it is left undefined DWR will use the global settings.
Regarding your problem I can see that you have overridden the global path setting in web.xml:
<init-param>
<param-name>overridePath</param-name>
<param-value>myOverriddenPath</param-value>
</init-param>
This will instruct DWR to send its Ajax requests to “/myOverriddenPath” instead of to the DWR servlet’s configured contextPath/servletPath. Note that this setting will not configure DWR to actually appear on the new path but assumes you are using path rewriting in your web server setup or similar.
As things start working when you assign p._path = dwr._pathToDwrServlet (the value of the servlet’s configured contextPath/servletPath) I would guess you have a problem with your path overrides or path rewrites.