Portal Prelude Error's

[Timezbrick]

I Installed Portal Prelude and now there are missing Textures, Props, etc.
It still works fine, But it isn't as it would be.. Does some one know how to fix it?

[Ad Bot]

[Dr.Block]

Do You have Half Life 2? I remember downloading a Portal mappack that required I have that installed. I'm not sure if that's the case with Portal Prelude.

[PowerDag]

Portal's update regarding Portal 2 did some weird stuff that broke Portal Prelude.