The hazards of themes using custom template files....
The default tiki-pagehistory.tpl file had been changed and I didn't notice to update Tikipedia's version (which only differs in the location of the page top/bottom links). Thanks for pointing out the problem.
It can be solved with a new version of tiki-pagehistory.tpl for this theme, which you can get here (save as tiki-pagehistory.tpl and upload to your templates/styles/tikipedia/ directory). The tikipedia.tar.gz package has the updated file. Sorry for the trouble.