Process model does not get triggered

I have setup TN RN doctypes, TPA’s, processmodel and focal role. When partner sends data , TN is able to recognise the doctypoe, sender and receiverid but processmodel which is subscribing for this TN RN xml doc is not getting triggered.Instead I am getting error, wm.tn.tpa:getTPA com.wm.app.b2b.server.ServiceException: Missing agreementID .
I checked the TPA and all the parametres in TPA match the parametres sent by partner.TPA is in agreed status and TPA name is same as TN RN xml doc type name.
Any suggestions will be of great help.I am using webmethods6.1

Thanks,
Meena

Forgot to mention that I changed the doctypename and agrementid.
TN RN doctype name and Agrementid are same. This change was required for modeler as modeler was not accepting “.” in the doctype name.
Any suggestions?

Thanks,
Meena