Forms data not saving to database

Please see http://www.sanjaykumar.us/index.php/cforms-ii-plugin-forms-data-not-saving-to-database/
This is exactly my problem. Usually it’s okay. But recently it sometimes happens that a confirmation/verification mail is sent and the data is not included in the database.
Question: What is the smartest way to change the IP-column size? I would like to hear your opinion.