I think she is passing the journals manually as opposed to using the inbuilt functionality.
Elena, once you create a journal and get the green 'the journal has been processed' message, you can't overtype the same journal again and just press post journal. Instead, when you get the green 'the journal has been posted' message, you need to hit the create button so it starts a fresh journal. What you're doing at the moment simply overwrites the journal you've just posted which is why it keeps disappearing.
Using the inbuilt Fixed Asset functionality is definitely worth a look but the above should help you for other journals so you don't run into the same problem.