DoxyBlocks was commited after the 10.05 release, so it is not in it.
Go to the nightlies subforum and install a nightly that has it.
p.s. I'll fix the info in the wiki...
Thanks for the quick reply! After reading it I saw that the DoxyBlocks' own wiki page does actually mention that it's not available in Code::Blocks 10.05... my bad, the main plugin page's list got me thinking it was and I didn't read far enough.
Thanks for referring me to the nightly builds; I should be able to work that out.