# Troubleshooting Lithium Installations This quick list is meant to cover common problems in installing Lithium. ## Internal Server Error Internal server errors are usually a result of bad .htaccess configurations. Make sure unmodified copies of the .htaccess files from the lithium repo are in these places: * `/.htaccess` * `/app/.htaccess` * `/app/webroot/.htaccess` You might also be running in a directory on your web server that is already under rewrite rules (often URLs that include your username such as http://username.example.com or http://example.com/~username/). This may cause 500 Internal server errors, or in some cases, cause a redirect loop. In this case you'll need to adjust your .htaccess files to include a RewriteBase directive: * `/.htaccess` => `RewriteBase /` * `/app/.htaccess` => `RewriteBase /app/` * `/app/webroot/.htaccess` => `RewriteBase /app/webroot/` Make sure to place the RewriteBase directive just after `RewriteEngine on`. ## Images/CSS Broken Usually this is a result of `.htaccess` files not being parsed. Make sure that the the directives that cover your Lithium installation include the following line: {{{ AllowOverride all }}} ## Unexpected Character Input If you get an error that looks like this: {{{ Warning: Unexpected character in input: '\' (ASCII=92) state=1 in /path/to/lithium/app/webroot/index.php on line 22 }}} This means you're not running PHP 5.3 or later. Please check your PHP version and update as appropriate.