What color do you have in the area of the eyes?
Where the eyes are on the texture (and some actually paint eyes here, is the mucus membrane of the eye socket.
If you make this area a color similar to Lacrimal, that should be what you see.

Lashes transmaps? Good is a matter of taste. But it seems to me that quite a few of the free textures for Vic also come with lashes transmaps.

If you have the skill to do it yourself, go for it. Only Mother Nature can take the skill away, once you have it.

For Vic the reason that the lashes have so many instances, is that each has two layers. For sparse lashes, leave off one of the layers.

I made the texture myself, so there aren't any eyes specifically to avoid this problem, just skin color. But you're saying this is avoidable, right? Could it have something to do with setting the colors inside Poser? I can't remember what the four settings are called, but I always set the first one to white. Would the others perhaps cause this black line problem?

It is all the same Material, so the color settings are not involved. If you do not have black on the main texture, then the lashes are the likelt couprit. Look on the transmap. See if there is a horizontal white line at what would be the roots of the lashes. You will need to creap black over the white. To test this: do a trial. Make the whole root area black. If the black line inside the eyelid goes away, this is it. If this is it, you have to go in increments to get far enough, but not too far, otherwise, you will have lashes hanging in space. A paint program with layers would allow you to keep this limit for any future transmaps you make and allow you to edit any you have from outside. Just open the texture and add the layer above it. A paint program with layers is almost a necessity for character textures.

the black is from the fold of the eye and cannot be removed unless some vertecies are removed which im sure you wont want to do