I can't speak for Lion, but the SUID messages in previous OS's could be ignored. It's beyond me why Apple hasn't fixed this issue because it just serves to alarm and/or annoy people. For more info than you ever want, read
Mac OS X: Disk Utility's Repair Disk Permissions messages that you can safely ignore. FWIW, I get a ton of them. At least you're limited to one (for the moment, anyway).
You can run Verify Disk without booting from the Recovery partition by launching Disk Utility as you did before. If everything is OK, you'll be told, obviating the need to go further. Otherwise, the procedure should be harmless at worst and helpful at best. I sympathize with your insecurity but rest assured that it's OK to do this.
Adding an account is a GOOD THING. I strongly urge you to do it.
