Some people don't understand or don't like the idea of wikis. They will sabotage any effort to even start a wiki project. Typically this happens in organizations where there are no wikis set up. Arguments against wikis range from “why not use emails instead?” to “there's already a document repository on the server”, “but I'm the owner of this information, and I will lose the ownership”, or “vandals will be able to screw up the wiki.”
There's resistance at either management or IT level. Typically this happens in document-oriented organizations where ownership is sacred. Many Wikiphobic people will print their emails and documents as they fear that these may get deleted, so the idea of online collaboration is completely out of the question.
Wikiphobic people typically are ignorant. Just create the wiki on a server and don't tell them it's a wiki. Tell them it's an informational web site and only trusted editors can modify it. Then add everybody as an editor except the Wikiphobic people. They'll think that the site is static and can't be modified, which will suit them very well. You will pass as the owner of the contents, and thus they will ask you to modify the site via emails. Just cut and paste the emails into the wiki. By the time they figure out it's a wiki, your wiki will likely be very large and they won't have the guts to delete all that information. They may ask you to disable editing. Answer “yes, I'll do it” but then just ignore the order. Repeat as necessary, typically every six months.