Error: Open item account line with flow type 0101 has to contain a partner

hi gurus,

while i run periodic postings for a contract a faced this error:

"Open item account line with flow type 0101 has to contain a partner"

"Message no. RERACA005"

i chcked all the configuration for flow type and reference flow type and all the assignments but it's still appears, anybody had faced and solved this error before and can guide please.

thanks