Image fiele not found

On one of my clients site your plugin is used and it works great. Unfortunately in one place there is problem with images. When you edit field in admin panel image is displayed correctly with such url

http://example.com/wp-content/files_mf/cache/th_d7568dd41591af86870e9d0d638cddbb_guzman.jpg

Here starts problem. In template using this code

$image_params = array("w" => 320, "zc" => "C", "q" => 95);
$image_src = get_image("department_head_profile_image",1,1,0,NULL,$image_params);

or even by using View button in admin panel under correct image I get url to non existing file

http://example.com/wp-content/files_mf/guzman.jpg. Is there any way to force this plugin to use correct images?

http://wordpress.org/extend/plugins/magic-fields/