Firefox 3: Extension Installation Error

Firefox could not install the file at

file:///D:/Downloads/Software/all-in-one_gestures-0.19.1-fx.xpi

because: Unexpected installation error
Review the Error Console log for more details.
-203

This is what I always got, no matter how many times I've re-installed my Firefox 3.
I've done what is written here. I've lost my extensions and I still will get the error back.
I've uninstalled my FF3 clean, even deleted my bookmarks, and extensions using RevoUninstaller. Redownload the installer of FF3. Then install FF3 again.

This is my fifth time trying to reinstall FF3. At first, I thought I can live with it since I already had my add-ons installed, but then realised I'm not able to update any of my add-ons, so I did the reinstallation.
Here's the chronology of my addons installation from the latest reinstall:
First of course, I've installed AdBlock Plus. Installed nicely, I've restarted my Firefox. Then I've installed Flashgot, then Greasemonkey. I can't live without mouse gestures, so I've installed All-in-One Gesture, the hellish error came to me AGAIN. As I am frustrated that the error keeps coming back, I feel like screaming the word "again" in front of my notebook.
Just to make sure the add-ons are downloaded correctly before installing, I've download the xpi using Free Download Manager first, then drag the files to FF3 to install.

Is there any way to be out of this hellish error? Other than leaving FF3 for other browser or go back to ver 2? I just don't understand why this error keeps coming to me, because I use well-known extensions and no experimental extensions. And I can't keep reinstalling FF3 forever...


UPDATE:
Jakpro found the fix to this annoying problem :

 

It just installed for me. Although I installed it from here rather than manually via the .xpi.

 

You mean All-in-one gestures?　I think you misunderstand a bit.
My problem is not that I am unable to install a specific add-on. But it happens randomly at the time I try to install an add-on. For example after I install add-on A, B and C, then it happens when I try to install add-on D. After that error happens, apparently it will keep happening when I try to install any other add-ons after it happens once.

At first、I too install immediately from the sites or the add-ons window in FF3, but the error comes so I thought I might want to try to download the xpi first than immediately install, just in case if the problem is a corrupt xpi download.

 

Are you running a firewall? If that is not an issue, then it is Firefox-centric. Did you install FF3 over the top of FF2 initially? When you reinstalled FF3, did you manually delete the Firefox profiles? It sounds like your FF profile may be corrupt.

 

I am running CPF, but I already set it to allow FF3. I do not run the Defense+.
When I installed FF3 the first time, I just did a clean install on my PC. Before that, I use Opera.
When I reinstalled FF3, I've checked all the Local Application Data and Roaming Application Data. The Mozilla folder is already empty because I uninstall FF3 using the advanced option from RevoUninstaller. My FF3 folder in Program Files are also clean.

Even from the time I've posted the thread, I've already retried the FF3 clean reinstallation three times. The problem persists.

 

Since you do not seem to be reticent towards wiping out FF and starting fresh, try this (provided you do not also have ThunderBird or some other Mozilla programs installed):

• Uninstall FF using Add/Remove programs
• Delete the Mozilla folder under Program Files
• Delete the Mozilla folder under Users\username\AppData\Local
• Delete the Mozilla folder under Users\username\AppData\Roaming
• If you want to, delete the Mozilla and Firefox registry entries via REGEDIT, too.
• Shutdown completely
• Restart
• Verify all the above folders are gone
• Reinstall Firefox 3
• Install your extensions from the Mozilla Add-on site

 

Of course, it is possible that it is a problem with Comodo, too.

 

I have the same problem as KarenA when I try to install more than 4 addons. I had tried deleting everything as the suggestion above, but it still didn't work. And I'm using Windows Firewall. To be honest I have got used to it, having 3 addons at the moment

 

I have 9 extensions right now, 1 of which I installed just today. I installed and then deinstalled a 10th today as well. I would not accept not being able to perform this function and would have to figure it out and fix it were it my machine misbehaving in that way.

 

I don't run Defense+, so I don't have the installation mode or whatsoever cause the whole Defense+ is disabled. So it doesn't fix my problem...

 

I would shut down Comodo and try to install the extension

 

I've closed Comodo completely, and the error is still showing.

 

Bummer!

And you have tried the steps here for Corrupt Extension Files?

 

I've tried the steps from that site. I even tried the profile thingy written there too. But not only I've lost all my add-ons, the error was also coming back as I install the extensions.

 

Did you try the big hammer approach back in post #6?

 

Do you have third party cookies disabled? According to this post on mozillazine, that could cause extension install errors.

 

Not working. Now I am unable to install Greasemonkey. D'uh Dear Mighty Firefox, please tell me how do I live with only four add-ons.

I keep it enabled. And my error message is different from the post on mozillazine.

 

Do you have UAC turned on? Have you tried starting Firefox from the Start Menu via a right-click/Run as Administrator? (You only need to do that one time - it remembers).

 

I have tried running as administrator, running in Firefox safe mode... Not fixing the issue.

I'm thinking to try living with it and hopes that FF3.1 fixes this issue.

 

I just started having the same issue with the same error.

I completely removed Firefox and all registry entries, rebooted, and re-installed and it is still giving me the same error.

 

I figured out what the problem was on Firefox for me!

Threatfire was blocking the installation of extensions. I disabled Threatfire and then installed the add-ons with no problems. I then enabled Threatfire and everything worked fine.

 

I kind of doubt that it is a FF bug, per se; rather, I feel that it may be an installation idiosyncracy. It would seem to be reported more widespread if it were a bug.

In any case, Firefox 3.0.1 is out.

 

THANKS!!!!!! It fix the annoying problem :laugh:

 

I've disabled ThreatFire and it worked! Thanks!! I hope it won't be coming back.

 

hmm i just updated to 3.0.1 and i get

Download error
-228

i reinstalled it and everything deleted the regs too turned off firewall and i still get this error help now i have no add ons

 

Glad you got it figured out. A good puzzler!

 

If you are using Threatfire, try suspending it, install your add-ons, and then take Threatfire off of suspend. You will have to suspend it anytime you add new extensions.

If you are not using Threatfire, disable your anti-virus program and try installing the extensions. You will run the risk of potentially downloading a virus if the extension is not a reputable source.