Thank you for a quick response. Here is the information that you had asked me to verify. There is only once instance of SForce connection. I am using my session information for my logon. 

1) Connection related code

<salesforce:Connection id="apex" serverUrl="https://www.salesforce.com/services/Soap/u/15.0"/>

            private function login ():void    {
                var lr:LoginRequest = new LoginRequest();
                lr.server_url = parameters.server_url;
                lr.session_id = parameters.session_id;
                lr.callback = new AsyncResponder(getReconData, handleFault);
                apex.login(lr);
               
            }
 

2)The query involves all custom objects. Object o is the parent of Object a and Object g in the following query. The query needs to involve them all to get the desired result. The following query runsusing APEX explorer pointing to API version 15.0. Even if there is an alternate to the following query [ which I would like to know], I sure would like to use the later version of the API to get outer join results.

Query

Select o.ID, (SELECT a.Id, a.Name, a.AdjustmentAmt__c, a.AirlineTicket__c, a.FinancialAdjDate__c, a.PerDiem__c, a.ObligationNbr__c
from Obligations__r a) FROM Obligation__c o
WHERE o.ID in ( SELECT Obligation__c
                         FROM GFMSReconIfce__c g
                        WHERE g.ProcessStatus__c = 'P')