Error converting type object to dataset, but I am not calling or using objects.

[Eagle_f90]

I have two sets of code, one to take a varilbe and grab info from SQL DB and fill a DS. The other to assign that DS to a local DS in the calling script. The problem I am getting is

Compiler Error Message: CS0266: Cannot implicitly convert type 'object' to 'System.Data.DataSet'. An explicit conversion exists (are you missing a cast?)

But it does not make senst to me since I never call anything an object both varibles are delcared as DataSet types.

    public static DataSet GetSQLDataSetByQuery(string SQLQuery)
    {
        SqlCommand cmd = new SqlCommand();
        DataSet ds = new DataSet();
        SqlConnection Con = GetCon();
        using (Con)
        {
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = SQLQuery;
            cmd.Connection = Con;
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            da.Fill(ds, "TResult");

            return ds;
        }
    }

Code with error:

            DataSet ds = SQLHelper.GetSQLDataSetByQuery(SQLQuery);
            DataBind();

As you can see in the code everything is a DataSet so I am not sure where the object is coming from.