What are you using the shader on. Is it just sitting on a brush quad with nodraw? Is it a patch or model (autosprite might have problems with those, BTW)?
What game is this for, and have there been modifications to autosprite or generated lens flares?
The shader itself looks right. You shouldn't need sort unless you have some other crazy shader stuff in the wall shaders. Here is one of mine, very similar:
rgbGen wave noise 0.9 0.1 0 30