Never able to delete a cast member

Every time I have tried to delete a cast member, I am DENIED! "Unable to Verify." Is there a secret way to do it that I'm not aware of? What criteria does IMDb use to verify and/or deny this type of correction? This is what I'm trying to do:

#210511-040301-762000

Film:  "Duds" from 1920 - tt0011139

Cast member: "Doc Phineas Kastle" - nm7169912

This guy is not in this silent film. He has nothing to do with this film. He wasn't even born when this film was made. Movie magazines from 1920 do not list his name in the credits. AFI does not list his name in the credits. 

Someone please help.

Thanks.