This plugin prevents users from commenting or viewing your website if a comment of theirs has been marked as spam.
SB stores banned IP addresses in a table called "wp_sb_ip_log". Plugin's settings can be found in the table "wp_options":
Delete your IP address from the table "wp_sb_ip_log" in your MySQL database.
Wait until spammer's cookie expires or use the slow method of detection of spammers. When the spammer visits your blog again, their cookie will be deleted.
Nothing. Duplicate records are automatically filtered.
Uninstall and install the plugin again. I try to avoid all errors that may be caused by updating to a newer version, but nobody is perfect, so this might help in the case that I forgot to prepare something for an update (typically new names of the plugin's options in the wp_options table in the MySQL database).
No. (That may change in the future.)
Post a new thread on the forum.