Can't upgrade CB 1.9.1 to 2.1.2

Joomla 2.5.28 installation of CB 2.1.2 ( from downloaded pkg file) shows following:
Failed to uninstall self. Please uninstall manually.
Failed
001_pkg_communitybuilder_2.1.2+build.2017.05.04.16.30.55.c67734e1f.zip

CB shows 1.9.1 still, with message "2.1.2 is an easy, free and highly recommended upgrade, compatible with Joomla versions 3.x and 2.5.x."

CB 1.x to CB 2.x is a migration. Please search as we've answered questions regarding this several times already.

www.joomlapolis.com/forum/146-general/235490-cb2-installation?limitstart=0

www.joomlapolis.com/forum/153-professional-member-support/234725-update-to-cb-2-0-15-and-cbs-subs-4-1-9-fail#285793

I have now upgraded Cb and CBSubs (CB upgraded by unzipping all packages and installing each file manually)
assuming that the cbsubs-eng-GB file is not an issue, everything is fine on Windows (firefox & Chrome) but a user on iMac, iPhone & iPad cannot log-in; I can log-in using their details on Windows but not on my iPhone; 'Please Log-in first' message is displayed...

[it was this user who first alerted me to the error '/e is deprecated' messages that prompted me to upgrade and hence this topic;these messages did not appear on my windows devices]

Don't see what desktop or mobile has to do with login not working. Login isn't device specific. Ensure all your Joomla menu items to CB have valid menu types by editing them within Joomlas menu manager as you may have a routing problem.

Sorry, It now looks as if this was a user panicing and sending me the wrong log-in details.
However, I now have a more serious issue with Cb upgrade on another site, this one Joomla 2.5.27. Using the same principles as for the previous upgrade, I attempted to upload the com_comprofiler.zip file; the result was a blank page; now all I have, front and back ends, is a blank page; the CB admin component does seem to have been updated, looking at Filezillas file list.

You installed the component for CB 2.0, but not its library. When you're migrating from CB 1.x to CB 2.x download the latest CB 2.x release then unzip the package downloaded and install the zip within the /extensions/packages folder.