Compatibility with Smarty v3
I just turned on Smarty v3 per the Civi Core warning and reports stopped working. When I disable this extension, they work again. It looks like the extensions isn't compatible with the Smarty3 update.
If it helps, I went into the extension directory on my local dev machine and just ran a civix upgrade (using the latest version of civix, 23.12.2) and it seemed to fix the extension. I can enable it again. I'm not sure if that's all that is needed, just wanted to point it out.