I'm so happy to know how to use parallax now!
Once again, thank you!

I'm glad I could help.

I thought this meant I should include the height map as the A channel of an RGBA .png file.
But looking at your node setup, the alpha channel is not being used. Instead the Value (RGB to grayscale) output is being used.
This must mean the true height data is being ignored. (But in Blender Internal the Texture nodes don't have Alpha output - so I don't see a way to isolate the alpha channel.)

"Value" of Texture node in node material is Aplna chanel, so it's not just a conversation of image from RGB to BW. What you read in documentation is related to setup of parralax using standart blender material (without using node system), otherwise you need to look in the Special Nodes section of documentation.

I thought that maybe my understanding was wrong, and I should use two separate images:

Normal Map
- and -
Height Map

In node system you can use separated Hieght Map, but put your height map to Alpha Channel of Normal Map texture is much more optimize and economy in recources.

Can I have multiple UV map in my node material ?

You can use maximum only 2 UV in node material. And only first 2 uv of mesh will be exported.

Добрая часть моих заказчиков- жители регионов, где только об Win XP и слыхивали, а вертикальная синхронизация как термин вгоняет их в православное "Оспдипамилуй".

Да, к сожалению в условиях российской экономики такое по России распространено и к примеру на заводе на котором мне довелось работать самый мощный комп который стоял (и стоит насколько мне известно еще) в отделе инновационных разработок куплен был в 2006 г. и все удивлялись на жалобы что он мол тормозит когда пытаешь открыть большую сборку он же "Самый мощный на заводе!". Поэтому такое положение по всей России с учетом нынешнего "крысиса" продлится еще долго.

There's some mistakes in yor file. At first, Blend4Web dosn't support node textures, so you can use only images as textures. At Second, glow in Blend4Web it's not the same glow effect like in Cicles. It's just emulate a glowing with bluring edges of the object with shadless effect, but it can't really light the scene, so you need to create light like Point or Sun or enable Environment Lighting to light your scene. In third, glow effect can be only used in node material with special Glow node. I changed your sample a little to show you how to use Glow node.
sample.blend

If all the settings are defined in the Texture Context, what is the node for? Am I missing something?

Yes, it's must be done in another way. I prepear for you an example using your texture. Some explanation: Hight map from Alpha chanel must be connected to Height Map Input in Parallax node, to the Input UV must be connected Output UV from geometry node, and then Output UV of Parralax node must be connected to the Input UV of Normal Map texture and then connected to the Material Normal Input. That the simple scheme.
Heres your Example

instead of removing i added a new one

On your choice.

Yup.

So, you can see an empty material slot under the last material like massager said. Delet it and all will be ok.

Ok..
I'm sorry but I just starting this work

Can you scroll under the MUREK material?

Не помогло

Можете прислать файл с изменениями?