After following 5 minutes installation procedure of WordPress 3.7.1 on Ubuntu 10.04 LTS server, the first issue came up while trying to install first plugin. WordPress asked for FTP credentials (Message: To perform the requested action, WordPress needs to access your web server. Please enter your FTP credentials to proceed. If you do not remember your credentials, you should contact your web host.) and even after providing them, did not proceed further. The issue was fixed by changing the owner of WordPress directory in the server. This can be done after logging in using Putty and using the following commands:
cd /var/www
chown -R www-data.www-data wordpress
Here wordpress is the name of the folder containing WordPress installation files and www-data is the owner. To know the owner, a php file (say, whoami.php) can be created with just one line as follows:
<?php echo(exec("whoami")); ?>
After running this file, the Apache owner is displayed. The same owner is used in the chown command. For more on this issue please check this.
The second issue of blank screen came up when it was desired to rename the folder containing WordPress installation files. For folder rename the standard procedure is to first go to WordPress Dashboard and then to Settings > General changing both WordPress Address (URL) and Site Address (URL) to new URLs that would be valid after the folder is renamed. Once these changes are made, the folder is to be renamed and now the new URL is supposed to work. But, the new URL just showed blank. This issue was fixed by clearing the cache from the PHP accelerator.