"rate limit for downloads exceeded"

[Rudy]

On my browser, when I try to download the .xpi's , I get a blank
window with the
words "rate limit for downloads exceeded". I've never seen this
before. Automatic installation
also doesn't work.

[Gerald Vogt]

That is probably an error of the mirror from which you have downloaded
the xpi. downloads.mozdev.org randomly picks a mirror. Sometimes a
mirror is down or out-of-date or does not work properly. It is usually
enough to try it again. You can try the direct download links from
moji.mozdev.org. Click with the right mouse button (if on windows) and
save choose "save link as..." Save the XPIs on your desktop. Then open
the add-ons manager from the Tools menu of Firefox and drag and drop the
XPIs into the open window. That should install the files...

Gerald