It looks like a value in your settings is causing this problem. When you were updating your settings what exactly did you change? Is there a single or double quote in any of the values you updated? There are issues using these characters within your settings.
If you cannot update the settings by logging in you can always check on them from the db directly. In here the WA Settings table will hold all of the setting names and values. You can find the one that you change and update it here.