Systat sending in SAP Adapter 46 Status b04b

Hi all wMusers,

We are running wM 4.6 with SAP adapter 4.6 SP5 on WIN2000 server! We are facing the problem that we send the idoc status ‘04’ back to the SAP system! But we don’t know why this status is generated!
Does anyone have an idea what this status means exactly for webmethods or does anyone have an idea how to prevent this case!

for generating systat idocs we use the service as pre-processing service in a routing rule!