The latest Redsn0w jailbreak also fixes sporadic issues with launchctl.
It is therefore highly recommended to install redsn0w 0.9.10b4 over redsn0w 0.9.10b3 or update Corona 5.0.1 untether to 1.0-4.
The root cause of iBooks issue fix was first identified by @xvolks who earlier patched the kernel sandbox by including @comex sandbox patches into the Corona GIT.
Last week @xvolks released a standalone tweak xBooks hat completely fixed the iBooks error on iPhone 4, 3GS, iPad and iPod touch. But then later he handed over the hack to Musclenerd and Chronic Dev team to package into Corona and Redsn0w 0.9.10b4
If you have already jailbroken your iPhone, iPad or iPod touch on iOS 5.0.1 using redsn0w, just re-run the latest version of redsn0w (download links below) in jailbreak mode or run corona 1.0-4 over your existing jailbreak. New jailbreakers, should use redsn0w 0.9.10b4 for clean untethered iOS 5.0.1 jailbreak iPhone 4, iPhone 3GS, iPod touch 4G, 3G and iPad 1G.
You’ll need to remove it and reinstall iBooks, in case you have already installed xBooks tweak on your jailbroken iOS device for iBooks fix. Make sure you de-select “Install Cydia” and do a controlled “slide to power off” shutdown of your device before running redsn0w 0.9.10b4.