I suppose the error was that when I write a reference to a tied hash the reference isteslf loose its object, it's just simply became a string whith an hex address.

I used separate hash both to store data on file with Tie::File::AsHash and to share with process using IPC::Shareable.

As said by some of you the reference are not managed, so I must take care of it.

Now everything works well. Thank to everybody