Have you tried:
– deactivating all plugins to see if this resolves the problem. If this works, re-activate the plugins one by one until you find the problematic plugin(s).
– switching to the default theme to rule out any theme-specific problems.
– resetting the plugins folder by FTP or PhpMyAdmin. Sometimes, an apparently inactive plugin can still cause problems.
– re-uploading all files & folders – except the wp-content folder – from a fresh download of WordPress. Make sure that you delete the old copies of files & folder before uploading the new ones.
I maybe have found the reason…the plugin which have caused troble was ‘disable comments plugin’, which is disabled and delated too. Before I have install this plugin the pages have worked fine.
I have also read the plugin developer faq, but I can’t find a solution, to fix this issue..
The mostly similar thread is here, but is not showed how to manually reset/restore the database….
http://wordpress.org/support/topic/plugin-disable-comments-permanent-mode-undo?replies=3
