For MS Access installtion
Included with this distribution is a populated MS Access database file that will allow you to use MS Access and ODBC to run phpBB 2.0.
Unzip the ms_access_primer.zip file in the db directory, place the resulting file somewhere appropriate (ask your hosting provider if you're unsure where the best or required place is to put this file)
You now need to create a System DSN for this file in your ODBC Data sources. The exact procedure again depends on your hosting provider. If you're unsure then ask them for assistance.
Open config.php in a text editor and uncomment (remove the /* and */ around) the ODBC - MS Access entry
Enter the name of you gave the data source where it says <HOST HERE>
If everything is set up correctly you should now be able to access your ODBC/MS Access powered phpBB 2.0 beta
MSSQL 7/2000
Both a schema and basic script are provided for MSSQL.
You should access your facility for running queries directly against your MSSQL DB, this is usually the Query Analyzer but may be different for hosted situations.
Log on to your database, you should then run the schema followed by the basic script (if no errors occured for the schema). You shouldn't encounter any problems. If you do, first check you have appropriate permissions to create tables, indexes, etc., check you're using your assigned database and not someone elses

If it still fails, post a bug report to sourceforge.