Alright, I found out what was wrong with the models not being loaded. They can be loaded, but apparently only if they are found in the model-path. Full paths don’t seem to work (I managed to load my files by removing the 3 first characters and adding ‘C:/’ to model-path). Can anyone concur or object that ?
And about the CollisionNode::add_solid issue I met, I opened a bug report with a few lines of code that reproduced the issue on three different builds of 1.9.0 ( bugs.launchpad.net/panda3d/+bug/1248551 ).