Upgrade from 1.7 to 1.8 CB

I try to upgrade to 1.8 and i receive a error "There was an error uploading this file to the server."

If i look in my extension manager and look at the comprofiler show me that the version, date and author is missing
comprofiler Administrator Component N/A 10060


System information
Joomla! 2.5.7 Stable
PHP Version 5.2.17

Thank you

check your installation guide.

This install from 1.7 to 1.8 is a simple install, i run this install in another joomla installation and run find no error at all, same joomla an CB version.

Can i unistall this 1.7 version of Joomla and reinstall 1.8