If you are using Microsoft Internet Explorer and are experiencing a Plug-in crash, or if the DjVu Plug-in is not loaded properly even though the installation was successful, please check the following points.

1. The Plug-in is not loaded properly, and an empty page with a small red [x] icon is displayed.

If you have just installed the Plug-in, and you are trying to display a DjVu document, but you are seeing this empty page, IE may be asking you to allow running the DjVu Plug-in. In this case, on the top of the page, there should be an information bar prompting "This website wants to run the following add-on 'DjVuControl Module' from 'LizardTech (unverified publisher)'. If you trust the website and the add-on and want to allow it to run, click here..."

If you click on the bar, a menu shows up. Please select "Run Add-on", then the document will be displayed properly.

2. The information bar is not displayed and just a small red [x] is displayed on the page.

This might happen to those who run Auto-installation on our download page. In this case, the DjVu Plug-in is disabled on the Manage Add-ons dialog:

You can reach this dialog from the menu Tools > Manage Add-ons...
Please find "DjVuCtl Class" and confirm that the status is marked as "Enabled". If it's not enabled, please select "DjVuCtl Class" and click the "Enable" button at the bottom right of the dialog.

3. The DjVu Plug-in crashes when accessing or closing a DjVu page, even though it worked properly before.

This might happen if you have installed the Plug-in some time ago. This is because you have installed other add-ons, and sometimes those add-ons cause a conflict with the DjVu Plug-in. If this is the case, you can fix this conflict by resetting Internet Explorer.
Please note that resetting Internet Explorer may wipe out your preference settings and bookmarks. If you try this work-around, please back up your preference settings and bookmarks so that you can restore them after resetting.

To reset Internet Explorer:
1. Select the menu Tools > Internet Options.
2. Select the Advanced tab.
3. Click the Reset... button.
4. In the Reset Internet Explorer Settings dialog, click the Reset button. Do not check "Delete personal settings" if you don't want to lose bookmarks and other preference settings. Please read carefully the caution in the dialog for details.

For more details about the IE crash problem, please reffer to these Microsoft articles:
Reset Internet Explorer 8 settings (Microsoft Website)
Internet Explorer stops responding, stops working, or restarts (Microsoft Website)