WORDPRESS

1. Fatal error:Call to undefined function wp() in /home/user/public html/wp-blog-header.php on line14

Solution:-
This issue is due to your wordpress wp-config.php content. For my case wp-config.php content was null. So i have copied the wp-config.php from backup and solve this issue.

or if you dont have one, there is one example:wp-config-sample.php change the name of that file to wp-config.php and change the database connection configures

2.Wordpress site very slow
This might be because of the plugins that you have installed on your wordpress site. Try disabling the last installed plugin or disable them all. To disable, you can follow the following steps
Cpanel --> PhpMyadmin --> Select Database -->> wp-options -->>select active_plugins(will be on page 2) -->>Edit
Copy down the plugins to somewhere else
Remove the plugins from there
Click GO
Then we can re enable it one by one form wordpress admin dashboard, so that we can find the plugin which caused the problem.
NB: If this solution is not successful, you can check these options: Upgrade to the Latest Version, Check With The Host, Optimize the Database, Verify That it Isn’t A Connectivity Issue,

3.Blank Pages in home page or admin page

This is due to recently added plugin , so we can avoid this by disable the last activated plugin by using your PHPMYADMIN[ select the particular database from wp_options > active_plugins]

or this may due to the wrong theme selection , all your wordpress themes are located on /wp-content/themes directory. So we can select the correct theme to "template" and "stylesheet" fields on your Phpmyadmin >> wp-options

*Idea from Dan Thompson

4. Warning: curl_setopt() [function.curl-setopt]: CURLOPT_FOLLOWLOCATION cannot be activated when in safe_mode or an open_basedir is set in /home/user/public_html/wp-content/plugins/web-traffic-genius-pro/curl_functions.php on line 80 or 37 etc

In this situation we need to check php.ini whether safe_mode set to OFF and open_basedir is comment out. In my case open_basedir was not comment out. So i have copied a php.ini file to wp-admin directory and change the line as ;open_basedir = "/home:/tmp:/usr"

5 Problems when trying to open a post from categories list.
or RSS Feed time out

Solution:- Try disabling all your plugins, then see if you can access the feed and the categories. If you can, you then need to re-activate the plugins 1 by 1 until you find which one is causing the site to stop loading correctly.

6 increase the upload size
Solution: copy a php.ini file on your home directory and paste the line
upload_max_filesize = 32M(your required size)