No... You don't need to edit the file at all. When you start the merger, you will be prompted for the details of the database to merge (you'll be asked for a host, an username, a password and the database name. You should fill those fields according to the database you want to merge.
For example, if you're merging a database located in the same server you're running vb, then the settings should be something like this:
db host: localhost
db user: user
db pass: password
db name: dbname
but if you're trying to merge a database on a different server, you should change the db host to the host name or IP address where the database is located. Note that you will need to configure your server to allow connections from other hosts (most hosting companies doesn't allow connections to the mysql server if you're not on the local server, but you can change this on your control panel, or ask your hosting company about this matter. I'm unable to provide support here).
Tell me how it goes, or contact me (again

) if you can't merge the database.
And remember, DON'T modify the script, you don't need to do it.