Title: fatal error when activate new theme
Last modified: August 19, 2016

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# fatal error when activate new theme

 *  Resolved [burselfwoman](https://wordpress.org/support/users/burselfwoman/)
 * (@burselfwoman)
 * [15 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activate-new-theme/)
 * I installed new theme, but when I activated it, my website’gone, & appear this
   message: **Fatal error: Call to undefined function register_nav_menus() in /home/
   sloki/user/k8026936/sites/burselfwoman.com/www/wp-content/themes/platform/sections/
   nav/section.nav.php on line 36**
    Please, HELP! I’m dumb, don’t know anything
   about all this stuffs. Help me with step by step. Many thanks.

Viewing 6 replies - 1 through 6 (of 6 total)

 *  Moderator [James Huff](https://wordpress.org/support/users/macmanx/)
 * (@macmanx)
 * [15 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activate-new-theme/#post-1834155)
 * You’ll need to access your server via [FTP or SFTP](http://codex.wordpress.org/FTP_Clients),
   navigate to `/wp-content/themes/` and rename the directory of your currently 
   active theme. This will force the Default theme (WordPress 1.5 – 2.9.2) or the
   Twenty Ten theme (WordPress 3.0 and higher) to activate and you should be able
   to access your Dashboard again.
 *  Thread Starter [burselfwoman](https://wordpress.org/support/users/burselfwoman/)
 * (@burselfwoman)
 * [15 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activate-new-theme/#post-1834384)
 * Hi James,
    Problem is solved. Thanks so much for your help.
 *  [iamidiot](https://wordpress.org/support/users/iamidiot/)
 * (@iamidiot)
 * [15 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activate-new-theme/#post-1834386)
 * Hey there, I’m having a similar problem and have tried the solution with no luck.
   I’m getting this error message whenever I go to my site’s wp-admin. Any advice?
 * Warning: Cannot modify header information – headers already sent by (output started
   at /home2/iamidiot/public_html/wp-content/plugins/ungallery/configuration_menu.
   php:302) in /home2/iamidiot/public_html/wp-includes/pluggable.php on line 890
 *  [Emil Uzelac](https://wordpress.org/support/users/emiluzelac/)
 * (@emiluzelac)
 * [15 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activate-new-theme/#post-1834389)
 * [@iamidiot](https://wordpress.org/support/users/iamidiot/) did you just install/
   activate new plugin? if so this could mean that your plugin isn’t compatible 
   with your WordPress version.
 *  [Emil Uzelac](https://wordpress.org/support/users/emiluzelac/)
 * (@emiluzelac)
 * [15 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activate-new-theme/#post-1834390)
 * Problem resolved for the original poster [@iamidiot](https://wordpress.org/support/users/iamidiot/)
   please open new topic.
 *  Moderator [James Huff](https://wordpress.org/support/users/macmanx/)
 * (@macmanx)
 * [15 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activate-new-theme/#post-1834391)
 * burselfwoman, you’re welcome!
 * iamidiot, you have unexpected whitespace (either a space or an entire line) on
   line 302 of the `/wp-content/plugins/ungallery/configuration_menu.php` file. 
   See [this guide](http://codex.wordpress.org/FAQ_Troubleshooting#How_do_I_solve_the_Headers_already_sent_warning_problem.3F)
   for more info.
 * Alternatively, replacing the file with one from a fresh download may resolve 
   the issue.
 * If that doesn’t help, please start your own topic.

Viewing 6 replies - 1 through 6 (of 6 total)

The topic ‘fatal error when activate new theme’ is closed to new replies.

## Tags

 * [Themes](https://wordpress.org/support/topic-tag/themes/)

 * 6 replies
 * 4 participants
 * Last reply from: [James Huff](https://wordpress.org/support/users/macmanx/)
 * Last activity: [15 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activate-new-theme/#post-1834391)
 * Status: resolved

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