BAPI - BAPI_ACC_GL_POSTING_POST

Hi there,

I am using the above BAPI posting documents with no problems at all.

However, if I use a posting date in the past i.e. 31.03.2008 the BAPI

returns the error message Period 12 is not allowed.

I have passed '12' as the fiscal period, '2008' as the fiscal year and '31.03.2008' as

the posting date. I must be missing something in order for the BAPI to work.

Any ideas anyone? Any help much appreciated and rewarded.

Thanks

Andy