It's important to confirm that you are using a truly closed boundary; if you get an error, it often means there's a tiny gap or that your boundary objects are not connected. Once you have ensured your boundary is closed, you can follow this simple guide to apply and adjust the ANSI37 pattern.
If you want to fine-tune your drawing setup, please let me know: autocad chevron hatch
The (e.g., wood flooring, brick paving, wall tiling)? It's important to confirm that you are using