The error is:

[wpsc_category_image] [wpsc_category_name]
Fatal error: Call to undefined function wpsc_print_product_list()

Sadly, according to Google, there are over 9,000 pages that have this error message on it.

Kind of scary to think of, isn’t it?

Why is this happening?

To put it simply, your widget is accessing old code and within that old code is a call to a function that no longer exists with the new version of WP e-commerce.

How do I fix it?

Follow the three steps below.

Step One: FTP into your site.

Using an FTP client, such as Dreamweaver, FTP into your website and access the wp-content/uploads folder.  Within the “uploads” folder, there should be a folder called “wpsc” and within that folder is one called “themes”

Step Two: Rename your theme’s folder

Depending on the theme you had activated previously, in my case it was “default”, rename that folder using your FTP client.

Step Three: Copy Files

In WordPress, go to Settings->Store and then to Presentation.  From there, check all of the theme/template files and then hit the “Move Template Files” button.  This will move them to your WordPress theme folder so you can customize them as much as you need.

Step Four: Refresh

Refresh your page. The error should be gone and your category widget should be appearing as normal.

Did these four steps work?

If these steps solved your problem, please be sure to share this post on Twitter, Facebook, Digg or Reddit, because there are many people just like you who are stuck with the same problem.

Photo By stuartpilbrow

Disabling Plugins

Before you start pulling your hair out, there are a few ways to debug and get around this issue.  Firstly,  if you can access the WordPress admin area, disable all of your plugins one by one and then check to see if your site is back to normal.  By using the process of elimination, you can narrow your debugging down to one single plugin.

However, if you are unable to access the WordPress admin area to disable plugins, you have two options: delete the plugin files or disable all plugins in your database.  If you have FTP access, then FTP into the /wp-content/plugins directory and start deleting.  This method isn’t recommended because you will essentially have to start from scratch.  If you have access to PHPMyAdmin and are comfortable working in this area, create an SQL query:

UPDATE `wp_options` SET option_value=” WHERE option_name=’active_plugins’;

This will disable all active plugins.

Now that all of those plugins are disabled and you are able to narrow it down to the pesky one, this leaves you with two options: you can either ditch the faulty plugin for a similar one, or you can attempt to fix the plugin’s issue.


Let the Author Know

Either way, it is a good idea to let the plugin author know about your issue.  When doing so, it is very important to provide as many details as possible.  Details include:  Which WordPress version?  What server type (Apache or IIS)?   What version of PHP?   What browser are you using?  What other plugins are installed?  What were you doing that may have caused the issue?


Debugging Options

Okay, so you’re feeling adventurous?  First off, you will need a helpful plugin called Error Reporting.  This handy plugin will create error logs for nearly everything in WordPress.  It will allow you to pinpoint which line in the plugin that the problem is occurring.   This is recommended for advanced users with PHP experience.


Conclusion

Sometimes things just break.    It’s important to take a deep breath and to keep an open mind.