fromApp method causes message reject with "Conditionally required field missing"

Hi,

I have a fromapp method defined as follows in QuickFix/J:

// Method to determine messages that we receive from the FIX Exchange (Non-administrator class messages)
public void fromApp(Message message, SessionID sessionId) throws FieldNotFound, IncorrectDataFormat, IncorrectTagValue, UnsupportedMessageType

{ MsgType mtype = new MsgType(); System.out.println(message.getField(mtype).getValue()); }

When I receive a specific message, though, I send out a reject with text "Conditionally Required Field Missing":

8=FIX.4.2 9=81 35=AQ 49=FLOB 56=6000 34=54 52=20081113-13:39:41.629 57=1 568=1 569=0 749=0 750=0 10=053

8=FIX.4.2 9=115 35=j 34=54 49=6000 50=1 52=20081113-13:39:40.420 56=FLOB 45=54 58=Conditionally Required Field Missing 372=AQ 380=5 10=213

I have also tried:

// Method to determine messages that we receive from the FIX Exchange (Non-administrator class messages)
public void fromApp(Message message, SessionID sessionId) throws FieldNotFound, IncorrectDataFormat, IncorrectTagValue, UnsupportedMessageType

{ StringField msgtypefield = new StringField(35); message.getField(msgtypefield); }

And I send out the same reject. When I leave the fromApp method blank, then I don't reject the messages (indicating that my data dictionary settings are fine). Also, I've checked in my Data Dictionary, and I have set all fields that I'm getting in the message (except for the header and trailer) to "N". Any help would be appreciated.

Thanks and regards,
Herman