problem with ExecuteStoreQuery

Question

 I'm using ExecuteStoreQuery to return needed data for a grid to client via ria services,

but the problem is when I run the load command on this Query it always gives me this error:

Load operation failed for query 'getMyData'. The result of a query cannot be enumerated more than once.

and it's the code of getMyData

public IQueryable<myDataType> getMyData()
{
    return this.ObjectContext.ExecuteStoreQuery<myDataType>("My Really Complex Query In here")
}

Any one has like this expreiance?