Accounts determination error is coming while create billing.

Hi Experts,

Accounts determination error is coming while create billing for Account Assignment Group A4 . In some cases only this error is appearing . I m a ABAPer I got this case and I  m debugging the code  . Can anyone  suggest me what all the things i need to check to know the root cause . This error is coming very  rarely but I want to find the reasons.  I saw some of scn post bt it was not clear .

Please suggest briefly what w'd be the probable cause of this error and how to correct it.

Thanks in advance