Translations:Installation - LimeSurvey CE/27/en
From LimeSurvey Manual
If you are using Linux, then setting permissions depends on your webserver configuration. For example, if you use Apache HTTPD on CentOS, type chmod -R 755 <directory> ; chown -R apache <directory>. This will give everyone access to read, and your webserver will have the permission to write. Check the following link for more information on Linux permissions.