Repair permissions problem - what is SUID file?

In the course of repairing disk permissions, using Mavericks bootable USB drive, i noticed that following message in the permissions report file:

Warning: SUID file “System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/MacOS/ARDAg ent” has been modified and will not be repaired.

Should I be concerned about this? What is it? Is there another way the file can be repaired???

All other permissions were repaired without issue except this.