before exporting, please go to Live View menu Materials/Octane Texture Manager, and check to have not any c4d shader in your materials, you should see only Imagetexture nodes listed in the panel.
Please note that most of the c4d native shaders are baked on the fly, but this automatic option slows down the process (especially in complex scenes like yours) because the textures are rendered and updated at every interaction, plus, not all the shader are completely supported. In particular, the **Layer** shader is not well support and you can have incorrect results, and instability.
When you have materials with c4d shaders, and you cannot replace them with Octane shaders, go to Live View, load the scene, then go to Octane Settings / Settings / C4D shaders, and change the resolution to the desired final texture resolution.
Then go to LV menu File / Export to... / Standalone scene (ocs) and save the scene, in this way a new folder named "assets" will be created with all the baked texture shaders inside.
Then replace all the c4d shaders one by one with an ImageTexture node, and the corresponding baked texture taken from the Assets folder.
In this way, the loading time and workflow will be faster stable, and more easily exported to Standalone and ORC.
I have been running into this issue as well and have lost many hours uploading files to find out there was always an issue. Would be good if Octane Standalone could detect these problems before the uploading process.
PS.: Thanks for your tip. It actually helped me, at least in some cases, other times it didn't matter, still got some errors.