I'm not sure anyone can diagnose this for you without registering for the site, so here are some suggestions for self-help.

Question: Did it work before and stop working recently? If so:

(A)

When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

1. Clear Firefox's Cache

orange Firefox button or Tools menu > Options > Advanced

On the Network mini-tab > Offline Storage : "Clear Now"

2. If needed, delete the site's cookies here

While viewing a page on the site, right-click and choose View Page Info > Security > "View Cookies"

Then try reloading the page. Does that help?

(B)

To rule out the possibility that an add-on is interfering, can you test in Firefox's Safe Mode?

First, I recommend backing up your Firefox settings in case something goes wrong. See Backing up your information. (You can copy your entire Firefox profile folder somewhere outside of the Mozilla folder.)

Next, restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the Safe Mode dialog, do not check any boxes, just click "Continue in Safe Mode."

If the window populates correctly, this points to an add-on or custom setting or perhaps a saved password as the problem. A few things to work through.

If the site doesn't load correctly, we would have to consider other factors.

Any luck?

Sorry, tried both but still the same. Works fine with Explorer and used to work in Firefox until I installed one of the updates several weeks ago.

I just noticed that the script name contains PDF. The "More system details" link with your original question does not show that you have the Acrobat plugin installed. If you open the Add-ons pane, does it show there?

orange Firefox button or classic Tools menu > Add-ons

On the left side, click Plugins. Then look for:

Adobe Acrobat 10.1.2.45
Adobe PDF Plug-In For Firefox and Netscape 10.1.2

If you uninstalled Adobe Reader and/or the plugin in favor of another PDF reader/plugin, then look for the appropriate plugin.

If the Adobe plugin should be there but isn't, you may be able to remedy that by reinstalling Adobe Reader. In some cases, you can copy a .dll file to a particular folder, but I don't have the relevant file and directory names handy.

If you do have the plugin but it isn't functioning correctly, you could try changing the way Firefox handles PDFs from viewing in the browser to launching Adobe Reader. Two places to check for this:

(1) Adobe Reader (or Acrobat) preferences

Edit > Preferences > Internet > uncheck the box for Display PDF in browser

(2) Firefox Application Options

orange Firefox button or classic Tools menu > Options > Applications

In the search box, type or paste pdf and pause while Firefox filters the list. Change the action in the right column to "Always Ask" and see whether that helps.

This is a workaround, and you might want to test again after the next Adobe and Firefox updates.

You've solved it! The Adobe plugin was disabled. Thank you so much.