[Mediawiki-l] 403 Error when adding or editing certain pages

[Azurite]

I don't know why this is happening, but on certain pages in my Wiki 
(which is up-to-date with ver. 1.6), whenever someone tries to add a 
page or edit them, they get a 403: Access Denied error. I have gotten 
this error when logged in from 2 different computers, and logged in (on 
both computers) with both a normal account and a SysOp account; another 
user has just emailed me saying she got the same error when she tries to 
preview or save the page in question. I have now gotten this with 3 
different pages on my Wiki, while other pages can be created and edited 
just fine. I have tried deleting the pages and starting over, but it 
doesn't help.

I've browsed through tons of Media Wiki documentation and other FAQs, 
including the archives of this ML, but nothing I find on Access Denied 
errors helps or applies to my situation.

Can anyone assist me?
Thanks,
~Azurite