wrong protocol sequence?

Hello!

    I'm sending such messages to server in native postgresql protocol:
'Parse' -> 'Describe' -> 'Sync' (get: 'Parse Complete' and 'Ready For
Query' messages back).
    But when the sequence became: 'Parse' -> 'Sync'  (get: 'Parse Complete'
and 'Ready For Query' messages back), little pause, 'Describe' -> 'Sync'
- server is crashing (error = memory can't be 'read')!

    My query is as simple as possible 'select * from table_name'. What am I
doing wrong?

    Big Thanks,
        Andrei