Oh, whoops. I was testing using different models as the pong ball. I guess it tried to use it for the flag, too, and gives those errors because the plant doesn't have the waving animations. That's not a problem with the build. It's just an ent file I made. Thanks for pointing it out, though.
Build 17 doesn't include new textures. If you want new textures, vote for them in the 2007 request thread. The primary focus of build 17 was the login system.
The filesizes files are warnings for your own protection. If you delete them, you won't be aware that what you're using could get you banned. While a clan logo on the jersy isn't really cheating, I don't have time or patience to sit down and verify every little tweak every player makes to his models/skins. Yeah, you might just be adding a clan logo, but somebody else might be making their model neon pink and stick through walls. I'm drawing a very simple clear cut line without grey area: either use the standard models and skins or get banned. If you get the warning, don't go online with it.