This problem is ultimately not serious. The system is trying to create a boot cache to allow your system to boot faster, but cannot because the access permissions for creating the cache are not as expected (or needed). The main system launcher "launchd" which is started by the kernel under the root account, is given the process ID of 1, which is why you see this error being associated with it. The launcher process is failing to start the "com.apple.kextd" launch agent, which is the configuration file for creating the kernel extension cache.
Without this cache the system will still boot fine, but may take a few seconds longer to do so.
First, back up all data if you haven't already done so.
Launch the Terminal application, copy or drag -- DO NOT TYPE -- the text below into the window, and press return. You'll be prompted for your password, which won't display when you type it. You may get a one-time warning not to screw up. Quit Terminal.
sudo chown root:admin /
That's odd. The kextd process does not interact with anything in the LaunchDaemons folder. The only thing I can think of is if the iStats plist was somehow interfering with launchd's ability to run the kextd process, but that's a bit of a stretch IMO. It might make sense if iStat installed a kernel extension, but it doesnt and instead only has a background monitor (daemon) that is managed by launchd through that plist you mentioned.
Regardless, its good to see that you got it fixed.
I don't know why either but installing an update to Integro Manager Pro creating the same error messages when I restarted the Mac (required to uninstall and reinstall the app) and reseting the permissions to the same file removed the error message. This is the plist file:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<string>/Library/Application Support/iStat local/iStatLocalDaemon</string>