invert effect not working?

[yumiifmb]

fig 1. is before adding the invert effect,

fig 2. is after adding the invert effect, the whole thing goes black instead of being inverted. Changing the channels doesn't fix the problem.

I tried doing it to a regular layer, and then to a pre-composed layer/composition. Doesn't solve it either.

Does anyone have any idea what the issue is?

[Mylenium]

Use Channel Combiner or any other similar effect.

Mylenium 

[yumiifmb]

I tried, it doesn't work. The problem is the same. What other similar effect are there?