Hmmmm... that doesn't give much insight onto what's going wrong, but I understand your reasoning for not posting the script here.
If you're using the "plrcanbeseen" condition, then you may want to make sure your level doesn't have a lot of obstructions around that could somehow prevent the top of the player from being seen (Invisible portions of entities perhaps? Not sure). Also, you may want to look into your entity's cone angle in their properties.
Sorry I can't help more than that. You can email me the script and when I find time I'll look at it more closely.
The one and only,