Receiver id is unknown

we are getting EDIFACT with the
Partner ISA (xxxxsome number )Qualifier --ZZ
Receiver ISA --some number Qualifier-- 01
I am getting receiver id as unknown and it is failing in TN
In partner profile i have set Mutually defined in external id the same ISA number we are getting in EDIFACT and in My enterprise Profile
same ISA number we are getting is given as Mutually defined in External id . I have checked the ids are matching still getting the error
Can any one help how to come out of this?

Please see munni post!
http://www.wmusers.com/wmusers/messages/117/26063.shtml?1075589697