this sounds like classloading issue or context path issue
The missing hr you get is probably becouse server returns 404 error page that is html that js client tries to parse as rpcxml...
Can you confirm that seam remoting servlet is in both cases listening on correct urls?
And do you maybe see any strange warn log messages while booting application? especialy ones that talk about remoting.
Also compare both boot logs and confirm that all same components are loaded in both cases.
we could go from there on...