Did you connect to the database? Can you connect to it from the Report Builder? If you can, then you *should* be able to see all objects (tables and views) as well as in TOAD.
If you can not connect to the database using Report Builder, do you get any error messages (different from ORA-01041)? Could you check the "alert.log" file? Is your database, perhaps, trying to shut down (or start up), but has problems doing it?
How about connecting to the database using SQL*Plus? If it is successful, perhaps you could help yourself by copying TNSNAMES.ORA and SQLNET.ORA from the database\network\admin directory into developer_suite\network\admin directory.