Problems running 64bit Virtual Machines in VBox even with a 64-bit OS

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http://askubuntu.com – So I'm running Kubuntu 12.10 x64: uname -v -p #29-Ubuntu SMP Fri Oct 19 10:26:51 UTC 2012 x86_64 and Virtual Box 4.2 installed from the VBox repositories. Any time I try to install a 64-bit OS as a guest the install fails and crashes w/ a kernel panic on Ubuntu or bombs in Windows 7 before it will boot. Am I missing something? (HowTos)