Title: invalid argument in plugin.php
Last modified: August 18, 2016

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# invalid argument in plugin.php

 *  [bc_nerd](https://wordpress.org/support/users/bcaplan/)
 * (@bcaplan)
 * [19 years, 2 months ago](https://wordpress.org/support/topic/invalid-argument-in-pluginphp/)
 * A bit of background for [http://www.digimediafinance.com](http://www.digimediafinance.com):
 * – Originally was adding categories to each post, that became cumbersome.
    – Now
   using Simpletagging plugin, seems to work fine – today I deleted the old categories
   as I intend to create a new category structure. Using wp-admin, I removed all
   but blogroll and uncategorized. – edited the name and desctiption field for Uncategorized
   to “digimediafinance/digimediafinance” as I want this to be the top of a hierarchy
   of categories
 * Now I notice that when I go to the categories page in wp-admin I get this error
   in my server logf file:
 *     ```
       PHP Warning:  Invalid argument supplied for foreach() in /home/www_digimediafinance_com/public_html/wp-includes/plugin.php on line 37, referer: http://www.digimediafinance.com/wp-admin/categories.php
       ```
   
 * If I add a new category, I get the same error and the page then displays as blank.
 * I tried changing the Category name back to Uncategorized, and the description
   back to blank, but I still get the same error.
 * Checking my log files, this error has never occured before.
 * Sys config info: self hosted on Centos4.3, MySQL version 4.1.20 blah blah blah.
 * Any tips or ideas on how to get this working again?
 * Thanks! Barry

Viewing 7 replies - 1 through 7 (of 7 total)

 *  Thread Starter [bc_nerd](https://wordpress.org/support/users/bcaplan/)
 * (@bcaplan)
 * [19 years, 2 months ago](https://wordpress.org/support/topic/invalid-argument-in-pluginphp/#post-543649)
 * hmm, the full error mesage didn’t display above, let me try again:
 * (slightly edited for formatting)
 *     ```
       PHP Warning:  Invalid argument supplied for foreach()
       in wp-includes/plugin.php on line 37, referer:
       http://www.digimediafinance.com/wp-admin/categories.php
       ```
   
 *  Thread Starter [bc_nerd](https://wordpress.org/support/users/bcaplan/)
 * (@bcaplan)
 * [19 years, 2 months ago](https://wordpress.org/support/topic/invalid-argument-in-pluginphp/#post-543652)
 * OK, a bit more info: I notice that in table wp_posts, the post_category field
   is set to 0 for all my posts. Which I think would be fine, except their is not
   cat_ID 0 in wp_categories table, only 1 (Uncategorized) and 54 (Blogroll).
 * Could this be the issue?
 * If so, which table is wrong?
 * Thanks!
 * Barry
 *  Thread Starter [bc_nerd](https://wordpress.org/support/users/bcaplan/)
 * (@bcaplan)
 * [19 years, 2 months ago](https://wordpress.org/support/topic/invalid-argument-in-pluginphp/#post-543653)
 * No, that doesn’t seem to be it either – just looked at a scratch wp database 
   I had laying around on a differnt domain and it is the same wrt category ids 
   as mentioned in the previous post
 *  Thread Starter [bc_nerd](https://wordpress.org/support/users/bcaplan/)
 * (@bcaplan)
 * [19 years, 2 months ago](https://wordpress.org/support/topic/invalid-argument-in-pluginphp/#post-543654)
 * Oh yeah the line in question is this one (I haven’t modified this file at all):
 * `foreach ( (array) $wp_filter[$tag] as $priority => $functions ) {`
 * It is found in funciton `apply_filters`
 *  Thread Starter [bc_nerd](https://wordpress.org/support/users/bcaplan/)
 * (@bcaplan)
 * [19 years, 2 months ago](https://wordpress.org/support/topic/invalid-argument-in-pluginphp/#post-543657)
 * fwiw, I just upgraded from 2.1 to 2.1.2 (latest) and still the same issues
 *  Thread Starter [bc_nerd](https://wordpress.org/support/users/bcaplan/)
 * (@bcaplan)
 * [19 years, 2 months ago](https://wordpress.org/support/topic/invalid-argument-in-pluginphp/#post-543658)
 * Hmm more strangeness but sataarting to look better. I added a caztegory via the
   Category box on the write post page. The first one left me with the same result.
   Then I edited (directly in the db) the Uncategorized category to have a different
   name. Then I added 2 more categories inteh write post form, and now I can display
   categories in the “manage” page of wp-admin.
 * Not only that I am not getting the errors in the apache error log anymore!
 * We will see what happens when I try to manage the categories and give them the
   desired hierarchy.
 *  Thread Starter [bc_nerd](https://wordpress.org/support/users/bcaplan/)
 * (@bcaplan)
 * [19 years, 2 months ago](https://wordpress.org/support/topic/invalid-argument-in-pluginphp/#post-543660)
 * Well that seemed to work OK. I guess I am happy now, as behavior is what I expect,
   and I have upgraded to latest.
 * Anyone have any idea what happened, just for the record?
 * If not, I hope this thread helps someone who might have the same issue someday(
   although I sincelerely hope you don’t have the same issue 🙂
 * Best,
 * Barry

Viewing 7 replies - 1 through 7 (of 7 total)

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## Tags

 * [invalid](https://wordpress.org/support/topic-tag/invalid/)
 * [plugins.php](https://wordpress.org/support/topic-tag/plugins-php/)

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 7 replies
 * 1 participant
 * Last reply from: [bc_nerd](https://wordpress.org/support/users/bcaplan/)
 * Last activity: [19 years, 2 months ago](https://wordpress.org/support/topic/invalid-argument-in-pluginphp/#post-543660)
 * Status: not resolved

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