Moving from CM10 nightly beta to CleanROM - signature verification failure

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http://forum.xda-developers.com – I decided to give CleanROM a try. Prior to this I had unlocked my bootloader and put CM10 nightlies on my One X. I am planning to modify a Motorola lapdock to use with my One X, but CM10's HDMI out is broken. The cleanrom instructions just say to use TeamWin (which I have installed), and to wipe + install their zip. I tried both the CleanROM 4.5 zip and the 5.1 preview build (not SP1). For both of them I get a signature failed error in twrp. I've looked all over the forums (xda, and cleanrom), and have not found a solution. Sorry if this is a newb question. I actually would have (HowTos)