Have a look into the SAP OSS note 1413158 - FMCF108 error during PR reassignment in your case.
Also check the KBA 1638852 - Error FMCF108 during reassignment
Have a look into the SAP OSS note 1413158 - FMCF108 error during PR reassignment in your case.
Also check the KBA 1638852 - Error FMCF108 during reassignment