It seems some required data is missing to Post the Document.
First see the Document through FB02 or FB03, to check the Status of the Doc.
Check the Completion Status, then you can try to post the Parked Document through FBV0.
Parked documents must always have entries in BKPF (with status 'V'),
VBKPF and entries in one or more of the following tables ususally
VBSEGS/VBSEGK/VBSEGD etc. If any one of these is missing then the
document will not show.
Also, for parked documents there are no entries in BSEG.
to carry out these types of corrections by manual deletions. However
there is a way you can delete this document yourself using
the function module PRELIMINARY_POSTING_DOC_DELETE (note 63060).
This function module deleted the VBKPF, VBSEGS and VBSEGK entries and
also modified the BKPF entry to give it status 'Z' in the field
BKPF-BSTAT - which means the document is now a 'Parked document which
was deleted'.