Corona (5.0.1 untether) apparently breaks `launchctl`; @planetbeing figured out what caused it, and I patched the package: upgrade to 1.0-2.

The launchctl issue also affects you if you used redsn0w to install the 5.0.1 untether. I have built 1.0-3, which can upgrade redsn0w users.

Update #2: The b2 version of redsn0w includes the launchctl-related fix by @planetbeing as mentioned by @saurik here and here. As usual, you can just re-run redsn0w in jailbreak mode over your existing 5.0.1 jailbreak (even a PwnageTool one), making sure to de-select "Install Cydia” if you do. Always be sure to do a controlled "slide to power off” shutdown of your device before running redsn0w.

Update #3: The b3 version of redsn0w fixes a problem where re-running redsn0w over an existing jailbreak would cause MobileSubstrate-based apps to stop running until MS was installed again. Now you can re-run the redsn0w jailbreak step without worrying about that (but still remember to de-select the "Install Cydia” option if it’s already installed).

TIP: If auto-detection fails and redsn0w tells you no identifying data was found, you can always pre-select the appropriate 5.0.1 IPSW using "Extras->Select IPSW”.