I am trying to jailbreak two different Apple TVs using Greenpois0n RC6.1. Both devices are running 4.2.1, and both are giving this error:

Code:
Hooking jump_to command
libusb:error [darwin_transfer_status] transfer error: timed out
After that error appears, the ATV reboots but is not jailbroken. I am running OSX 10.6.7 on a current generation Macbook Pro. I could find anything online as to what causes this error or what to do to fix it.

Full Log:

Code:
MacBookPro:MacOS matt$ ./greenpois0n 
2011-05-01 10:41:29.768 greenpois0n[455:903] Could not connect the action buttonPressed: to target of class NSApplication
2011-05-01 10:41:29.770 greenpois0n[455:903] Could not connect the action buttonPressed: to target of class NSApplication
2011-05-01 10:41:29.770 greenpois0n[455:903] Could not connect the action buttonPressed: to target of class NSApplication
2011-05-01 10:41:29.771 greenpois0n[455:903] Could not connect the action buttonPressed: to target of class NSApplication
Initializing libpois0n
No matching processes belonging to you were found
Device must be in DFU mode to continue
Device must be in DFU mode to continue
opening device 05ac:1227...
Checking if device is compatible with this jailbreak
Checking the device type
Identified device as AppleTV2,1
Preparing to upload limera1n exploit
Resetting device counters
Sending chunk headers
Sending exploit payload
Sending fake data
libusb:error [darwin_transfer_status] transfer error: timed out
Exploit sent
Reconnecting to device
Waiting 2 seconds for the device to pop up...
opening device 05ac:1227...
Preparing to upload iBSS
Checking if iBSS.k66ap already exists
Preparing to fetch DFU image from Apple's servers
Fetching Firmware/dfu/iBSS.k66ap.RELEASE.dfu...
Uploading iBSS.k66ap to device
Reconnecting to device
Waiting 10 seconds for the device to pop up...
opening device 05ac:1281...
Setting to configuration 1
Setting to interface 0:0
Preparing to upload iBSS payload
Loaded payload for iBSS on k66ap
Resetting device counters
Uploading iBSS payload
Executing iBSS payload
Initializing greenpois0n in iBSS
Checking if device is already jailbroken
Booting jailbreak ramdisk
Preparing to upload ramdisk
Executing ramdisk
Setting kernel bootargs
Preparing to upload kernelcache
Checking if kernelcache already exists
Fetching kernelcache.release.k66...
Resetting device counters
Hooking jump_to command
libusb:error [darwin_transfer_status] transfer error: timed out
Exiting libpois0n