SQL Injection protection in CodeIgniter

[eluser]Razican[/eluser]
Hello, I have an application which inserts post data into the database. The problem is that if I put sth', 'sth in the text field, it creates a database error, because it tries to insert two fields data in only one:

INSERT INTO md5_decryptor (characters,md5) VALUES ('sth', 'sth','29f14c6f1851e7766ae69fdf4ca0c1c3');

I have the global XSS filtering enabled.