IDOC status 51, please respond quickly its urgent

Hi Guru's,

I have an issue with the Inbound IDOC.

I have a zfunction module which will post the zidoc, I have used the FM IDOC_write_to Database to update the status of the posting. I have used BDC to post Vendor Master and Customer Master i.e. FD01,FK01 tcodes.

<b>I am getting the status 51</b> <b>"EDI: idoc<idoc number> is already open in process mode.</b>

how to get rid of this error.

Thanks in Advance,

Sagar