I just fixed this on my new iMac. Let me know if the same works for you...
What was strange is that the Finder would not show this file /Library/StartupItems/Icon that the error message referred to. It turns out the file was invisible but only as a side-effect of its odd filename.
To view the file I went into Terminal.app (in Utilities) and used the following (in case you are not familiar with Unix, don't type the $ - it's a prompt):
$ cd /Library/StartupItems
$ ls -a
The following were listed:
. EyeConnect MxBtDaemon VirtualBox
.. Icon? RetroRun WDBMService
In my case (can't speak for anyone else but would be interested to know if you find the same) the '?' on the Icon filename was not actually a question mark, but a non-printable character.
To remove it is simple, unless you are not the owner of the file (which I found that I wasn't because I have kept my old account separate and I'm starting a fresh one because the old one is a bit messy).
$ rm Icon*
If this doesn't work (because permission is denied) you will need to do it a slightly different way:
$ sudo rm Icon*
Type your password and the file should disappear. You can check by running 'ls' again:
$ ls -a
. EyeConnect RetroRun WDBMService
.. MxBtDaemon VirtualBox