Dear experts
I was also facing the same error yesterday . As one of the members (Harish Menon) in the Team suggested , I deactivated the Customer exit EXIT_SAPLV60B_010 .
Actually we wanted to explore this exit and just wrote a message statement as follows :
MESSAGE I000(SU) WITH 'HELLO' .. And then we activated it . From then on this error has started happening . .
Now we have deactivated this user exit . Invoices are getting posted in SD .
Thanks .