I have some custom objects in our instance. I can run a query through APEX and get results. But when I run the same query through my .NET code (I have the latest WSDL and updated my web reference) , there is soap exception saying that the object is invalid. Here is is error : urn:fault.enterprise.soap.sforce.com:INVALID_TYPEINVALID_TYPE: sObject type 'XXXX_XXX_XX__c' is not supported.

Am I doing something wrong ? or is there some quirk I need to know.

Please help !!!