After upgrading wordpress to 2.7.1…wordpress admin panel dissappeared and replace with this error message:
Fatal error: Cannot redeclare uninstall_plugin() (previously declared in /home/username/public_html/blogfolder/wp-admin/includes/plugin.php:XXX) in /home/username/public_html/blogfolder/wp-content/plugins/pluginstaller/uninstall.php on line XXX
From the error message, It seems that there is an issue with plugininstaller pliugin. Please login into the FTP client and remove plugininstaller directory and all files/folders within wp-content/plugins/ directory. Once you remove this folder it will resolve the issue.