Error VBox rc=-1908 in Backtrack

/etc/init.d/vboxdrv setup
 * Stopping VirtualBox kernel modules                                                                                                                 [ OK ]
 * Uninstalling old VirtualBox DKMS kernel modules                                                                                                    [ OK ]
 * Removing old VirtualBox netadp kernel module                                                                                                       [ OK ]
 * Removing old VirtualBox netflt kernel module                                                                                                       [ OK ]
 * Removing old VirtualBox kernel module                                                                                                              [ OK ]
 * Trying to register the VirtualBox kernel modules using DKMS
Error! Your kernel headers for kernel 3.2.6 cannot be found at
/lib/modules/3.2.6/build or /lib/modules/3.2.6/source.

 * Failed, trying without DKMS
 * Recompiling VirtualBox kernel modules                                                                                                              [ OK ]
 * Starting VirtualBox kernel modules
 * modprobe vboxdrv failed. Please use 'dmesg' to find out why