Can't revert backup when migrating

Hello, I'm using Joomla 2.5.28 and CB 1.9.1. I want to update to 2.0 and I've read other posts about it. I know it is a migration, but my problem is that I can't revert to a backup. I've tried to install the 2.0 package and I get the message: Failed to uninstall self. Please uninstall manually
I haven't got any CB plugins. I am going to update to Joomla 3.5 and I can't lose all my information. Thanks for your help

Donwload the last CB package (just CB) then unzip it and within the /extensions/packages folder is the actual CB Joomla package extension. Install that and it should work fine. Our package installer is not tested for migrations (it has been something like 2 years now.. we are not doing those tests anymore.. sorry).

It worked! But I have the same message when trying to install the Spanish language plugin! How can I solve it?
Thanks

Finally I found how to do it. After installing it, I've got two Spanish language plugins: the first, that wasn't compatible with my current version, and the new one. I also have the English plugin, that is the default language. I'd like to know if I can delete the old Spanish plugin and how can I make the new one as default language instead of the English one.

Thanks

Default Language is English so you don't need an English language plugin. You can also delete your old incompatible Spanish language plugin. The language CB uses is entirely based off Joomla. So if you want the default to be Spanish then set the default language within Joomla to Spanish.

Perfect! Thank you!!