You have the latest update to Java which made some security changes. Some of this may be duplicative, but just in case...

You might have noticed in the past there was a little warning the dialog where you approved the page's Java applet to run that it was unsigned or some other issue. Those unsigned applets now are completely blocked if you have set "High Security" in the Java Control Panel.

Try clearing Firefox's cache, and emptying the Java cache before relaxing security.

(1) You also can clear Firefox's cache completely using:

orange Firefox button (or Tools menu) > Options > Advanced

On the Network mini-tab > Cached Web Content : "Clear Now"

If you have a large hard drive, this might take a few minutes.

(2) To clear the Java cache, first open the Java Control Panel (in the Windows Control Panel in the Programs category, at least on Windows 7)

Then see this article for details: How do I clear the Java cache?

The reload the page and see whether eBay offers an updated applet that doesn't have the security problem?

To check/change your security level, open the Java control panel, then see this article for more information on the slider and where you can enter site exceptions: http://docs.oracle.com/javase/7/docs/technotes/guides/jweb/jcp.html#security

You might try this:

(1) Move the slider to Medium temporarily

(2) Reload the eBay page and see whether you get a dialog to approve the applet and save the site as an exception

(3) Move the slider back to High after saving the exception, assuming you trust the source

Does that work?

References:

• Java™ SE Development Kit 7 Update 51 Release Notes

• New security requirements for RIAs in 7u51 (January 2014) (Java Platform Group, Product Management blog)

In another thread, a volunteer posted this link that describes all the different Java security messages, what they mean, and if there are options for making site-specific exceptions. Hope this helps:

What should I do when I see a security prompt from Java?

Starting in Java 7 Update 51, sites that would normally be blocked based on your Java Security settings can be added to an Exceptions list, via the Java Control Panel. See the Java Help page How can I configure the Exception Site List? for details.

Ref: http://kb.mozillazine.org/Java#Java_security_prompts

P.S. See this Java Help page:

• http://www.java.com/en/download/help/java_blocked.xml Why are Java applications blocked by your security settings with the latest Java?

Under "Applications where this issue may be seen include:" (at the bottom of the page) it specifically mentions "Ebay and Paypal Shipping Label"