Mediawiki error: File upload not working

I've installed Mediawiki v1.24.1 on my server which is running RHEL7. I've installed it under /var/www/foohelp/wiki. However, when I try to upload a file, I get the following error: [f3eae72a] /foohelp/wiki/index.php/Special:Upload Exception from line 1871 of /var/www/foohelp/mediawiki-1.24.1/includes/filerepo/file/LocalFile.php: Could not acquire lock for 'User-default.png.' Backtrace: #0 /var/www/foohelp/mediawiki-1.24.1/includes/filerepo/file/LocalFile.php(1174): LocalFile->lock() #1 /var/www/foohelp/mediawiki-1.24.1/includes/upload/UploadBase.php(738): LocalFile->upload(string, string, string, integer, array, boolean, User) #2 /var/www/foohelp/mediawiki-1.24.1/includes/specials/SpecialUpload.php(467): UploadBase->performUpload(string, string, boolean, User) #3 /var/www/foohelp/mediawiki-1.24.1/includes/specials/SpecialUpload.php(186): SpecialUpload->processUpload() #4 /var/www/foohelp/mediawiki-1.24.1/includes/specialpage/SpecialPage.php(363): SpecialUpload->execute(NULL) #5 /var/www/foohelp/mediawiki-1.24.1/includes/specialpage/SpecialPageFactory.php(584): SpecialPage->run(NULL) #6 /var/www/foohelp/mediawiki-1.24.1/includes/MediaWiki.php(275): SpecialPageFactory::executePath(Title, RequestContext) #7 /var/www/foohelp/mediawiki-1.24.1/includes/MediaWiki.php(584): MediaWiki->performRequest() #8 /var/www/foohelp/mediawiki-1.24.1/includes/MediaWiki.php(435): MediaWiki->main() #9 /var/www/foohelp/mediawiki-1.24.1/index.php(46): MediaWiki->run() #10 {main} If I edit /includes/filebackend/FileBackendGroup.php and modify LockManager to 'lockManager' => 'fsLockManager', and modify permissions as follows: chown -R apache:apache images/ chown -R 755 images/ I get the following error: (Could not create directory "mwstore://local-backend/local-public) I've tried most of the forums and there is no solution that seems to fix my problem. Any help would be appreciated.