4 component JPEGs are usually JPEG files saved by Photoshop in the CMYK colour space.
Support was added for these types of JPEG files in Indigo 3.6.10.
Please update your Indigo version to 3.6.10 or newer: http://www.indigorenderer.com/forum/viewtopic.php?f=1&t=12296

This is a new xml tag introduced in Indigo 2.4. The error is caused by having an exporter that is 2.4 compliant, but a version of Indigo that is lower than 2.4.
To resolve this error, simply update to the latest version of Indigo. Download

It is likely that Indigo is not installed in the default location.
For SketchUp:
If you do not have Indigo installed at the typical location (Applications), go to Plugins->SkIndigo->Set Indigo Path.
Then, browse to the location of the Indigo application.

Indigo now supports PNG files with 2 components.
Please install a recent Indigo version such as 3.6.11: http://www.indigorenderer.com/forum/viewtopic.php?f=1&t=12309

This error is caused by two processes trying to use the same network port. Make sure there is not an old Indigo.exe running (check the Task Manager - Ctrl+shift+esc > Processes) before you open a new Indigo process.

This is likely caused by Indigo autosave feature not being able to save at that location due to permissions. To fix this problem, run Indigo as Admin.

Indigo supports loading GIF files since version 3.6.8.
Please install a recent version of Indigo such as 3.6.11: http://www.indigorenderer.com/forum/viewtopic.php?f=1&t=12309

This PNG file was not correctly saved by the program that created it. Try re-saving it using an image editor such as Photoshop.

Default-meshes.igs is an igs file that contains the mesh information of a scene. It is referenced from a main igs file and cannot be rendered by itself, you must open the main file (either default.igs or a set file-name) to render.
This file is created separately and referenced so that a exporter can export either just mesh data, or all other data without having to rebuild the meshes (which is usually the longest part of an export). This feature is known as "Quick Export".

Look through your material settings, chances are you will have one of your material attributes set to 'shader' with no shader set. If you are trying to use shaders, make sure you refer to the shader documentation in the manual.

This error is caused by the scene requiring more RAM than you have available. Indigo has been tested with scenes up to 30 million unique triangles and creating images bigger than 10 megapixel - but if you do run out of RAM - there are several steps you can take to address this:

Improve your pc:

1. Ensure you are running a 64 bit operating system (32-bit Windows can only allocate 2GB of memory to Indigo)
2. Buy more memory. Indigo works great with 4, 8 or 32GB of ram
3. Don't try and run multiple renders concurrently

Change the scene:

1. Decrease the Supersample factor.
2. Turn off Aperture Diffraction. This feature uses a substantial amount of memory.
3. Decrease the amount of light layers. Each layer contains enough memory for a whole image.
4. Render at a smaller resolution.
5. Downsample the textures you use
6. Simplify the geometry of your scene
7. Use instancing. With instancing Indigo can render literally trillions of triangles in a scene.