The file should be located here: wp-content/plugins/spammer-blocker/
You can retrieve the backup by clicking the “Make a backup” button. After that a message with a link pops up and you can either save the file directly or open it in your MS Excel.
You can use it to import lots of IP addresses (you can avoid typing them manually in the form on the plugin’s settings page by using this file).
Also remember that the plugin automatically bans all authors of comments marked as spam when it is activated; it is also able to do it up to twice a day automatically.
I hope that this plugin will work well for you. If you have any questions/problems don’t hesitate to contact me.
(PS: Sorry for my broken English in the previous post, I reedited it badly before sending and now I cannot change it.)