1. How indigo version you use?
2. How indigo exporter version c4d plugin you use?
3. If you export the scene without the specific material causing the bug, does the error disappear?
4. Probably while reinstalling Indigo 4 you have overwritten c4d plugin and it doesn't read shaders "def 4 bla bla bla", try installing c4d plugin separately from the forum to a newer one (relatively new)
5. various kinds of compatibility errors occur when opening a material file of an old version of indigo .igm .pigm and saving it in a new version of indigo, after resaving the material, the file structure may be broken and it will not display correctly for longer. you need to initially rebuild it from scratch in the new version of indigo.
http://www.indigorenderer.com/materials/materials/895
example material before / after save .igm code