Info_texlights is not an entity in normal Half-Life, but only in the mod. Spirit of Half-Life.  I assume that you are using Spirit or a mod. based on it.

In order to get textured lights to function, you need:

• A file or entity that contains lighting information about the texture that you want to use.

Normally the lighting information is parsed from an external file, lights.rad.  Texture lighting information looks like this:

TextureName     Red  Green  Blue  Intensity

For example, GENERIC87A  100  255 100 1000

The colours take values in the range 0-255, and the intensity is anything you like, though it must be much higher than entity light values; values of 5000 are common, and even 50000 if the light texture is very small - the smaller your light fitting, the higher you need to make the intensity, since the actual brightness in-game increases with the size of the light fitting.

In at least some versions of Worldcraft/Hammer, this file is initially almost empty of information.  There is another file in the editor directory, called valve.rad, which contains the missing information.  Replace the data in lights.rad with the data from valve.rad if this is the case.

In the case of Spirit, you can use an entity - info_texlights - within the map to specify texture lighting.  The advantage of this is to allow you to specify unique light values for each map, without editing lights.rad every time.  The info_texlights should overide lights.rad.

• It needs to be in the right place, so that the compiler can parse from it.

This doesn't apply to info_texlights, but lights.rad must be in the same directory as your compile tools.  This is not necessarily your Hammer directory!

• You need a map that uses this particular texture.