Call to undefined function set_status_header()

[eluser]jzmwebdevelopement[/eluser]
I have a client using CI 1.7.0 and I have the following error can anyone provide any light to this?

Code:

Call to undefined function set_status_header() in /system/libraries/Exceptions.php on line 118

The line is

Code:

set_status_header($status_code);

[eluser]plain jane[/eluser]
The <code> set_status_header() </code> function was added in version 1.7.2.

Please refer <url>http://ellislab.com/codeigniter/user-guide/changelog.html</url>

[eluser]plain jane[/eluser]
The <code> set_status_header() </code> function was added in version 1.7.2.

Please refer http://ellislab.com/codeigniter/user-guide/changelog.html