sh-3.1$ bitbake x11-image
NOTE: Psyco JIT Compiler (http://psyco.sf.net) not available. Install it to increase performance.
NOTE: Handling BitBake files: \ (0487/4973) [ 9 %]NOTE: <type 'exceptions.NameError'>:name 'base_version_less_or_equal' is not defined while evaluating:
    ${@base_contains('COMBINED_FEATURES', 'pci', 'madwifi-ng-modules', '',d)}     ${@base_contains('COMBINED_FEATURES', 'usbhost', 'kernel-module-zd1211rw', '',d)}     kernel-module-ieee80211-crypt     kernel-module-ieee80211-crypt-ccmp     kernel-module-ieee80211-crypt-tkip     kernel-module-ieee80211-crypt-wep     kernel-module-ecb     kernel-module-arc4     kernel-module-michael-mic     '${@base_version_less_or_equal('KERNEL_VERSION', '2.6.23', 'kernel-module-aes', 'kernel-module-aes-generic', d)}' 
ERROR: name 'base_version_less_or_equal' is not defined while parsing /home/nice/SlackPAD/oe/org.openembedded.angstrom-2007.12-stable/packages/tasks/task-base.bb
NOTE: Handling BitBake files: \ (4973/4973) [100 %]
NOTE: Parsing finished. 4739 cached, 1 parsed, 233 skipped, 0 masked.
ERROR: Parsing errors found, exiting...

<task-base>
...
RRECOMMENDS_task-base-wifi = "\
    ${@base_contains('COMBINED_FEATURES', 'pci', 'madwifi-ng-modules', '',d)} \
    ${@base_contains('COMBINED_FEATURES', 'usbhost', 'kernel-module-zd1211rw', '
',d)} \
    kernel-module-ieee80211-crypt \
    kernel-module-ieee80211-crypt-ccmp \
    kernel-module-ieee80211-crypt-tkip \
    kernel-module-ieee80211-crypt-wep \ 
    kernel-module-ecb \
    kernel-module-arc4 \
    kernel-module-michael-mic \
    '${@base_version_less_or_equal('KERNEL_VERSION', '2.6.23', 'kernel-module-aes', 'kernel-module-aes-generic', d)}' "
...