1. Are there any special precautions at the land registry services in order to avoid errors when opening a new file?
No, just deep analysis of attached documents.
2. If an error occurs and a land registry file describes the same immovable for a second time, what is legally determined to do?
According to art. 626.1 (13) Code of Civil Procedure the warning about a.m. fact should be placed in chapter 3 of each land book. Its character is to abandon legal presumption of public trust.
Is there a different procedure depending on whether the new file repeats totally a previous file or only a part of a previous file?
No, it is not.
3. Once the error is identified what happens to the rights and the charges registered in both files? And what about subsequent entries?
See answer 2
4. Is there any internal (intra-system) land registry procedure to solve this sort of problem or does it require judicial intervention?
It is internal LR procedure to place a.m. warning, but judicial intervention is needed to agree the content of each land book and to decide which file should be closed and which one should stay open.