This page provides help for specific error messages that sites may encounter when using PmWiki. If this page doesn't answer your question, try looking at Troubleshooting and frequently asked questions. If these still don't have the answer you're looking for, try the pmwiki-users mailing list or ask a question on the Questions page.
Something (or someone) has changed the permissions on the wiki.d/.flock file or the wiki.d/ directory such that the webserver is no longer able to write the lockfile. The normal solution is to simply delete the .flock file from the wiki.d/ directory -- PmWiki will then create a new one. Also be sure to check the permissions on the wiki.d/ directory itself. What should the permissions be?
AFAIK, read and write permission for your webserver account (e.g. www:www or apache:apache, 0750)
See also File Permissions.
Note that on many systems .flock is a hidden file, so it may still be there even if you cannot view it. Try deleting it anyway even if you don't see it in the wiki.d/ directory.
One other possibility is that you have recently moved the wiki and you were previously using EnableIMSCaching. Disable EnableIMSCaching in your local/config.php file and that could fix the problem RussFink? (this information subject to review)
Yet another cause may be that the wiki.d ownership has been moved out of reach of the webserver. e.g. Running Apache2 server as user www-data and deactivating its suphp module would disallow it to write the .flock file under the users permissions. In such a case, one should change the directory permissions for wiki.d to that of the user under which the web server runs. (this information subject to review)
In my case, the issue is caused by copying files which changed the owner of wiki.d directory. i fixed this error by "chown -R wwwrun ../wiki/wiki.d/". Hope it helps.
In my case, it seems that I have gotten this error because of problems at a broader level on my system. I was unable to delte the .flock as recommended above, so I tried to write files, upload files, mkdir at many places on my server and it seems that although the permissions look OK, for some reason I am not able to write to any file. I called my provider and they are looking into it. Therefore this error, in my case, is probably due to systemwide problems and not something specific to pmwiki. I discoverd this because I tried to copy .flock before deleting it as recommended above and I could not even make a copy.
One more possible cause could be safe mode. Check your logfiles for errors like SAFE MODE Restriction in effect. The script whose uid is 1001 is not allowed to access /www/wiki/wiki.d owned by uid 52 ... In this case you either have to turn off safe mode, or change the user/group to the user/group PHP is using (for hosting companies this usually is the user you use to log in) and set permissions to 0777 (that is - write for everyone) or turn off safe mode.
Skin templates are now required to contain <!--HTMLHeader--> and <!--HTMLFooter--> directives. Some skins developed under older versions of PmWiki failed to include these required directives, thus causing some PmWiki features and recipes to work improperly.
To work around this issue, do any of the following:
$EnableSkinDiag=0; in a local customization file.
PmWiki was able to find a requested skin, but couldn't find an appropriate .tmpl file to use as a template. If you have a custom skin, make sure there is exactly one .tmpl file in the skin's directory. (See skins and skin templates.) If you downloaded a skin from the cookbook?, make sure the skin was installed correctly, or contact the skin's author for more assistance.
PmWiki was unable to find or load the Site.EditForm page containing the form used to edit pages. Often this occurs when the wikilib.d/ folder isn't completely copied to the webserver, or when a read password has been placed on Site.EditForm or the Site group. Double-check that all of the distribution files are correctly copied on the webserver, and that authors have read permission to the Site.EditForm page.
PmWiki is attempting to do something that requires modifying pages or files on the filesystem, and the administrator has set the $EnableReadOnly configuration variable.
PmWiki is attempting to obtain information from an LDAP server (e.g., via authuser.php and AuthUser), but the PHP software doesn't appear to have the ldap_* functions available. PHP may have been built without support for LDAP (see http://www.php.net/ldap ).
Ubuntu users: install php5-ldap and restart apache. -drdaan? December 31, 2009, at 02:22 AM