Olá Luís.

If you have Java correctly installed and enabled in Firefox (check by going into Tools > Add-ons > Plugins), you may be having a problem with some Firefox add-on that is hindering your Firefox's normal behavior. Have you tried disabling all add-ons, except Java (just to check), to see if Firefox goes back to normal?

Whenever you have a problem with Firefox, whatever it is, you should make sure it's not coming from one of your installed add-ons, be it an extension, a theme or a plugin. To do that easily and cleanly, run Firefox in safe mode and select Disable all add-ons. If the problem disappears, you know it's from an add-on. Disable them all in normal mode, and enable them one at a time until you find the source of the problem. See this article for information about troubleshooting extensions and theme. You can troubleshoot plugins the same way.

If you want support for one of your add-ons, you'll need to contact its author.

Thanks Morbus.

Unfortunately, it didn't help... the same hapens only with Java plugin enabled!

This site also doesn't work properly in Safari so... it sounds to more like a Mac Os problem (Java for Mac) rather than configurations stuff.

If someone has a work around, woul'd be very helpfull.

P.S. Please, try the site your self and check it out.

Yes, it's working perfectly on my Windows 7 machine. You should contact BPI. Banks sometimes forget that there is more OSs other than Windows XP...

Make sure that you have the latest Java for your OS. You may be out of luck with Mac OS X 10.4 (no Java 1.6)

http://www.apple.com/downloads/macosx/apple/application_updates/javaformacosx104release9.html