Are you updating to 1.0.15? Why are you doing that now? That version was released several years ago and that version is no longer supported. I as remember, you had to upload the files with ftp and not use the Joomla Installer.
Migrate your site to a current version of Joomla. You have to migrate in several steps (1.0->1.5->2.5)
yes! I have joomla! 1.0.15
This version of the site for one of my friends
I asked for help because of the large amount of data stored in the site
And I want to help him to update his website
Then do step update (1.0->1.5->2.5)