Upgrade from 4.2.7 to 4.7.13 fails during DB 4.4alpha1 update Joomla
I see where the problem is happening and I have a solution, but from the CSV you're sharing, I can't see why the problem is happening.

Next time, before upgrading, go to your CiviCRM root and then open CRM/Upgrade/Incremental/php/FourFour.php.  Around line 543 will be a function called activityContacts().  CiviCRM changes how activity contacts are stored in version 4.4+, and this function is meant to facilitate that.

The first several lines are meant to look up the option value records labeled "Activity Source", "Activity Assignees" and "Activity Targets" and set them to be "reserved", so they can't be changed.  Based on the SQL in your error, it's not finding "Activity Assignees" - but I don't understand why, your CSV looks fine.

Regardless - you can fix this by ignoring the lookups and manually change the SQL query to use the values that I can see in your CSV file.

Change these lines:

    $query = " 
UPDATE civicrm_option_value
SET    is_reserved = 1
WHERE  option_group_id = {$optionGroupID} AND value IN ($ovValues)";


to this:

    $query = " 
UPDATE civicrm_option_value
SET    is_reserved = 1
WHERE  option_group_id = {$optionGroupID} AND value IN (1, 2, 3)";


Re-run the upgrade and you should get past that error.