Comment 1 for bug 732730

That's just a warning, the actual crash is trying to read the settings.xml file.

Committed a fix in https://github.com/jpobst/Pinta/commit/5245c63cd4af1d0fc0f7a22163719a7305e7e5bc to just default settings if your settings file is somehow unreadable.

You can probably fix the issue by deleting your settings.xml file.