Error: An error occurred due to no connection

This error is for Nov RTM running under "NETWORK SERVICE" account.

I created a data source "MyDataSource". It looks like:
<DataSource xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:dwd="http://schemas.microsoft.com/DataWarehouse/Designer/1.0" xsi:type="RelationalDataSource" dwd:design-time-name="2d2b4fc8-af5c-4314-9155-384afd11fb70" xmlns="http://schemas.microsoft.com/analysisservices/2003/engine">
<ID>MyDataSource</ID>
<Name>MyDataSource</Name>
<CreatedTimestamp>0001-01-01T05:00:00Z</CreatedTimestamp>
<LastSchemaUpdate>0001-01-01T05:00:00Z</LastSchemaUpdate>
<ConnectionString>Provider=SQLOLEDB.1;Data Source=dbserver\my_instance;Integrated Security=SSPI;Initial Catalog=MyDataSource</ConnectionString>
<ConnectionStringSecurity>Unchanged</ConnectionStringSecurity>
<ImpersonationInfo>
<ImpersonationMode>ImpersonateServiceAccount</ImpersonationMode>
<ImpersonationInfoSecurity>Unchanged</ImpersonationInfoSecurity>
</ImpersonationInfo>
<Timeout>PT0S</Timeout>
</DataSource>

In my package, I obtain a new connection from the data source (test connection succeeds). I use a data flow task. Inside the data flow task I have a flat file source and an Ole Db Destination. For configuring OleDbDestination, I can see in the drop-down a list of tables in my database. When I select the desired table and click "preview", I get:
TITLE: Microsoft Visual Studio

Error at Data Flow Task - my task [OLE DB Destination [831]]: An error occurred due to no connection. A connection is required when requesting metadata.

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ADDITIONAL INFORMATION:

Exception from HRESULT: 0xC0202022 (Microsoft.SqlServer.DTSPipelineWrap)

BUTTONS:

OK
TIA,
Nitesh

Can you please check that you are not working with "Work Offline" settings.