I can replace it will the old file if needed.
What I think happened their is either some bad permissions or server configuration issue which is causing packages not to install correctly on the board. I would reset all permissions using the package manager then try a reinstall.
I've managed to install the package but right now i still can't send the newsletter as i'm still getting this error
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(ID_LETTER,email)
')' at line 2