Cannot install addon in FireFox - dowloading error

[Oren10]

I am not able to install a addon in my Firefox browser. I want install a google toolbar on my browser. I received the error message "download error 228".

[Magnus]

I think your add-on is not compatible with your browser.
Each internal file in add-on shows the range of the browser's version.
You have to first update your Firefox version. To updated manually, click on help menu and then click on check for updates. After the updation restart your browser.

[Walter89]

Hey there,
You are receiving the error, may be your software installation is disabled.
You have to just check out whether is enable or disable.
But this can void your warranty. so just take care.
In the address bar type the following about:config and press enter.
You will receive a warning page " This might void your warranty! "
Click on I'll be careful, I promise!, to continue to the about:config page.
After that, in the Filter textbox, type xpinstall.enabled
The value for the above text should be set to true.
If the was false, then software installation is disabled.
For changing the value to true, right-click hold down the Ctrl key while you click the property name, and select Reset.
Try to reinstall your addon.
This will resolve your issue

[Alexander102]

Manytimes, by default Firefox only allow to install add-ons from trusted sites only. If the site is not a trusted one, a yellow bar pop up at the top of web page. Showing a message that Firefox does not allow to download the file.
You can add the website form which you are downloading the add-ons by :
In the yellow bar click on > Edit OptionsPreferences.
Then go on the Allowed Sites - Add-ons Installation dialog, in list insert the current website.
Now the current site URL is inserted into the text field.
Then click on Allow > close.
Now you will be able to install your add-ons form that site.