Whenever I open an HTML or CSS file, I get an error:



I would rather have HTML validation than not, but even when I delete the path to CSE Validator in Tools > Settings, it does not persist when I restart PHPEd. I have to perform this step every time I start PHPEd.

PHPEd v 4.0

I'd recommend you update to version 4.6 or just reinstall what you have (4.0) to refresh CSE Validator's configuration.

Surely there's a way to just disable validation? Reinstalling would require downloading again. Also, wouldn't I loose all my settings?

No, I think most of the settings will be preserved. Just save registry under this key:
HKEY_CURRENT_USER\Software\NuSphere\PHPEd4.0

Alright, thank you.