Texture Paint Problems

I am trying to color a character. I have unwrapped him and in GIMP I gave him the colors. When I put him back into Blender, there were still some areas that were not colored. Also There was a part I wanted to add color to but on the unwrapped texture, it was hard to see, so I wanted to color it in Blender.

Here is the problem: When I go into texture paint, I cant paint. I choose a color and drag the mouse but nothing happens. So I fiddled around with the settings and all I could end up doing is coloring with black and no other color (despite the color choice, black still prevailed.) Any ideas as to why Texture Paint is not working?

Thanks in advance.

Some outlining area within 3D screen, fail to paint for me some times too. Try changing point of view, or move the model around, and don’t have prospective turned on.

I tried that, but it still doesn’t paint for me. Thanks though