I'm trying to upgrade from 2.65. I uninstalled 2.65 and then installed 2.69c per the readme instructions. I then uninstalled 2.69c and when I try to install the com_dtregister2_7_2a_J15 component I get the following Error:
* JFolder::files: Path does not point to a valid folder or the folder has been deleted.
* JFolder::folder: Path does not point to a valid folder or the folder has been deleted.
* JFolder::files: Path does not point to a valid folder or the folder has been deleted.
* Error! Could not find a Joomla! XML setup file in the package.
Warning: array_merge() [function.array-merge]: Argument #1 is not an array in /var/www/gsoc/libraries/joomla/installer/helper.php on line 142
Warning: array_merge() [function.array-merge]: Argument #2 is not an array in /var/www/gsoc/libraries/joomla/installer/helper.php on line 142
Warning: Invalid argument supplied for foreach() in /var/www/gsoc/libraries/joomla/installer/helper.php on line 187
Might also try increasing your php memory_limit. Also, check in the Joomla system info area and make sure your permissions are all ok. If you can't sort it out, submit a ticket so we can see what in your site is keeping it from installing.
You can also try the Install from Directory option.