> Could you double-check that you do not mix files compiled with different
> versions?

Yes, that's impossible it was on a clean system. Here's another error
I get in another example :

error loading shared library: ...: undefined symbol: caml_young_ptr

Is the whole runtime system missing to them ? Note that these errors
happen with both loadfile and loadfile_private

> Then, please send a reproduction case (with source code and build
> instructions) to the Caml bug tracker.

Will do this evening.

Best,

Daniel