Try running the IrisLauncher as Administrator. You would receive that error if the launcher needs to update some files in the Iris folder but cannot for some reason.

Perhaps permission issues (likely), or trying to overwrite a file that is already open (possible but unlikely), or you may have the Iris Online folder nested deep in a lot of other folders and the filepath is too long, or you have a non-latin language setup and the Iris Online folder is inside other folders using non-latin language characters (unlikely).

First thing I would do is run it as Administrator.
If that doesn't work, try restarting your computer.
If the problem continues, try moving the Iris Online folder to your Desktop or directly to the C: or D: drive.