removing field from dbconfig

hi all,

i am new to GNATS, so please forgive i the question seems naive - but i
have at least tried to look into the archives...

i am trying to configuring a bug database. more precisely, i would like to
remove a field. consider the field "Confidental" as example. I removed
that field and any occurence of it from the dbconfig file of the database.
(the only changes to the default dbconfig file.)
then :
  send-pr --request-id --database db
seems to be successfull, and the index file seems to be properly filled.
however, query-pr pr-edit fail with the message
  "Index file /usr/local/share/gnats/vb2/gnats-adm/index contains
  incorrect number of fields"

in a next attempt (after a clean install of the db) i furthermore changed
in the dbconfig file the entry
  binary-index=false

send-pr again seems to work and query-pr does not fail, but the output is
obviously not correct. the category entry has been garbeld:

  >Number:         1
  pendingry:
  >Synopsis:       <One-line summary of the PR (one line)>

(note: 'pendingry:' instead of '>Category:       pending').
the pr-edit now fails with the message:

  pr-edit: Can't open file `'

am i doing something seriously stupid? it is just not allowed the
delete/change field? or did i hit a bug?

tia, heinz-dieter conradi