The website isn't using parameterized queries, which is a fairly serious security flaw. Most likely, your mother is putting a single quote in a field where the programmer didn't expect it, and because ...

Don't be afraid of using your chosen database's command-line client. I might as well say this up front: I don't like using GUI (aka non-command-line or graphical) tools with my databases. This is ...

This is an error in the spelling or grammar used when coding. Missing a letter, character or forgetting to include inverted commas/speech marks are common examples of ...