Question: I want to commit binaries when i create a tag, those binaries are .gitignored and git-add says "Use -f if you really want to add them." So, i wonder if this would be a safe thing to do or not.
I want to use this to checkout binaries on a target computer. The old "system" is to keep old versions in a subdirectory named by the date that version was compiled on, which is a little annoying.

Answer: 
This is more of a comment than an answer, but I need more reputation points to create a comment (*hint, hint*).

When debugging a problem like this it can be helpful to look at the error code in the NotesException object. Assuming you are catching NotesException, what is the value of the public `NotesException.id` field? That should map to one of the constants in the NotesError class (e.g. `NotesError.NOTES_ERR_DBNOACCESS`).

Also, your original question only shows 5 lines of the stack trace. The root cause of the exception may be further down. Can you include more of the stack trace please?
The Problem is that the db ist not found. So try to change the path from the db. if your db is in a folder on the server give the path for the folder in java. Your path variable must have the right format.
In your case for Example it must be
session = NotesFactory.createSession();
db = session.getDatabase("mail01/xxx", "pathToDB/aaa.nsf");