[Plugin: User Domain Whitelist] Translation of Error Messages

How to translate the error messages? Is there a way to do using Poedit?

I.E. Every time a user informs an email included in the blacklist, the app shows a message like this: “Error: …”. In Portuguese should be “Erro: …”, but the word Error I didn’t find a way to translate.

http://wordpress.org/extend/plugins/user-domain-whitelist/