"renderer not found error"

[micheus]

Should i install 1 by 1 the renderers?

yes. They are third part applications.

How to do that?

You have to download Kerkythea (check the link bellow) and tell Wings3D about the .exe file location by using the main menu Edit->Plugin Preferences->Kerkythea.

What is the best (most professional) renderer for wings 3D?

Well, as I'm a hobbyist I can't answer that, but I like Kerkythea because I can use its UI (user interface - the stand alone app) to change materials details not exposed by the Wings3d plugin.

You have also the option to install POV-Ray and Yafaray plugins (both software are free too). You can find information about them in these threads:
- Kerkythea Rendering Software
- YafaRay Rendering Software;
- POV-Ray Rendering Software