Title: Fatal Error when activating new plugins
Last modified: August 19, 2016

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# Fatal Error when activating new plugins

 *  [designer2008](https://wordpress.org/support/users/designer2008/)
 * (@designer2008)
 * [17 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-new-plugins/)
 * I get the following error any time I activate a new plugin:
 * Fatal error: Call to undefined function register_sidebar_widget() in /home6/typetheo/
   public_html/wp-content/plugins/smart-youtube/smartyoutube.php on line 542
 * This doesn’t seem to be affecting my admin or site, though it is worrisome that
   I get an error every time a plugin is activated. Any thoughts?

Viewing 10 replies - 1 through 10 (of 10 total)

 *  [iridiax](https://wordpress.org/support/users/iridiax/)
 * (@iridiax)
 * [17 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-new-plugins/#post-928863)
 * Check for an updated version of your theme and check out:
 * [http://codex.wordpress.org/Widgetizing_Themes](http://codex.wordpress.org/Widgetizing_Themes)
 *  Thread Starter [designer2008](https://wordpress.org/support/users/designer2008/)
 * (@designer2008)
 * [17 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-new-plugins/#post-928866)
 * I am running the most updated version of my theme. I did upgrade to the latest
   version of Smart Youtube today, and the problem seemed to immediately follow.
 *  [iridiax](https://wordpress.org/support/users/iridiax/)
 * (@iridiax)
 * [17 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-new-plugins/#post-928871)
 * According to the changelog, the latest version of [Smart Youtube](http://www.prelovac.com/vladimir/wordpress-plugins/smart-youtube)
   has “added support for sidebar widget videos” so you would need a widget-ready
   theme.
 *  Thread Starter [designer2008](https://wordpress.org/support/users/designer2008/)
 * (@designer2008)
 * [17 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-new-plugins/#post-928936)
 * I’m not sure I understand how the link you posted pertains to the issue I’m trying
   to solve. Sorry if I’m missing something obvious.
 *  [iridiax](https://wordpress.org/support/users/iridiax/)
 * (@iridiax)
 * [17 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-new-plugins/#post-928943)
 * Does your theme let you use widgets?
 *  [Navjot Singh](https://wordpress.org/support/users/navjotjsingh/)
 * (@navjotjsingh)
 * [17 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-new-plugins/#post-928973)
 * Yes, this happens only on 2.7 version of Smart Youtube plugin. Added the tag 
   to notify the plugin author.
 *  [bagheadinc](https://wordpress.org/support/users/bagheadinc/)
 * (@bagheadinc)
 * [17 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-new-plugins/#post-928981)
 * You can fix this by editing the following lines in the **smartyoutube.php** file…
 *     ```
       // register widget
         if (function_exists('register_sidebar_widget'))
         if (function_exists('register_widget_control'))
       ```
   
 * Just use the function_exists command like this…
 *     ```
       // register widget
         if (function_exists('register_sidebar_widget'))
       	register_sidebar_widget('Smart YouTube', 'yte_widget');
         if (function_exists('register_widget_control'))
       	register_widget_control('Smart YouTube', 'yte_widgetcontrol');
       ```
   
 * It will still register the Smart YouTube widget and you will no longer get that
   error whenever you activate a plugin.
 *  [Vladimir Prelovac](https://wordpress.org/support/users/freediver/)
 * (@freediver)
 * [17 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-new-plugins/#post-929029)
 * Fixed in version 2.7.2 🙂
 *  [Navjot Singh](https://wordpress.org/support/users/navjotjsingh/)
 * (@navjotjsingh)
 * [17 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-new-plugins/#post-929049)
 * Thanks for the quick fix. Here is one more problem and a suggestion too.
 * Your plugin in the sidebar says insert HTML code or the video link. But the problem
   is that it parses only httpv code. Nothing else. If I want to write something
   in the bottom of the video in sidebar using HTML code, it does not parses it.
   Moreover, the widegt does not give any option of titling the widget? I should
   be able to title the widget with something of my choice as latest videos. Pls
   add these features to make widget feature more useful.
 * Also your comment form at smart youtube post is not allowing my comment asking
   me to enable javascript and cookies where infact they are already enabled and
   plugin status shows the same too. Pls fix that error too.
 *  [Navjot Singh](https://wordpress.org/support/users/navjotjsingh/)
 * (@navjotjsingh)
 * [17 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-new-plugins/#post-929050)
 * One more thing..even your Blog’s forum is not allowing any new post showing blank
   page after posting in your support forums. So only way to report errrors was 
   this which I am using.

Viewing 10 replies - 1 through 10 (of 10 total)

The topic ‘Fatal Error when activating new plugins’ is closed to new replies.

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 10 replies
 * 5 participants
 * Last reply from: [Navjot Singh](https://wordpress.org/support/users/navjotjsingh/)
 * Last activity: [17 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-new-plugins/#post-929050)
 * Status: not resolved

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