Missing flashlight textures
It cant show up in the texture browser, because there is no VMT file for that texture (thats why there is the error in the console).
Are you sure your env_projectedtexture is bright enough? Sometimes you simply can't see it if it's to dark.
Another thought: do you have an entrance elevator in your map? The standard elevator instances have their own env_projectedtextures, which will turn on and override yours when the game starts. You need to explicitly turn it on via a trigger when the player enters the room.
Other Portal 2 maps: Medusa Glare
Portal 1 maps: Try Anything Twice | Manic Mechanic
The env_projectedtexture was already being triggered on and off by a button, but I added a trigger_once just before you entered the room, and turned the brightness up to a factor of 3. At first it didn't seem like either was working. However, by placing my cube on and off the button, I found I could get the light to turn on sometimes.
SO. . .technically I know the texture is there now, just not displaying properly. On top of that, I now know that the appearance field isn't affecting the projectedtexture, so the flourescent flicker that I want isn't going to work by doing it this way. Time to try a new approach.
Thank you guys so much for your help, though.
Arc8ngel Productions