I do have 3.3, and I used the ones in this thread
https://www.mobileread.com/forums/showthread.php?t=88004 and updated the only way I know how how...put the hacks in the root directory and then unmounted and went to Settings and selected Update from the menu on the Kindle. AFAIK those are the support for >=3.2.1.
0.10.N_k3g jailbreak and 0.27.N_k3g ss and 0.39.N_k3g usbnetwork hacks.
I had existing hacks, but I ran their uninstallers to upgrade to these. There's the possiblity one failed at some point, as I wasn't always watching the screen and the particular error message doesn't stick around for long.