RDB-Salv shall not be altered (patched). Those who do this anyway, should not be surprised by extremely uncomfortable side-effects. You are explicitly warned against removal of the registration number requester.
Of course, RDB-Salv shall not be distributed if it has been altered -- even when the altered software was based on the freely distributable version.
If a modification is thought to be useful, it's worth your while to contact the Author, who may after all have the desired function in the next version.