Hang on a tick. You've want to:
1) Move your database from SQL 7 to SQL 2000
2) Upgrade your WebWiz forum from 6.34 to 7.
These are two different steps and I would do them separately.
Step 1 (Moving database from SQL7 to SQL 2000)
Use DTS or whatever tool, to simply move / upgrade your existing database from the SQL 7 to SQL 2000 platform. This will keep the same database structure and you can continue to use WWF V6.4 with the SQL 2000 version of your database.
Step 2. (Upgrading WWF from 6.34 to 7)
Yes there are structural changes to the database. I believe there are migration tools available, so someone may be able to help you out with that. Try a forum search on this topic.
Cheers,
Andrew