open_basedir restriction in effect despite file directory within web root When trying to upload a logo to my Zen 3.1 subtheme (Appearance > Settings) I get the following error:

Warning: is_file(): open_basedir restriction in effect. File(/tmp/phpillr69) is not within the allowed path(s): (/home/testwww/web/) in image_get_info() (line 126 of /home/testwww/web/informator/includes/image.inc). 
Warning: realpath(): open_basedir restriction in effect. File(/tmp/phpillr69) is not within the allowed path(s): (/home/testwww/web/) in drupal_realpath() (line 2177 of /home/testwww/web/informator/includes/file.inc). 
Warning: getimagesize(): Filename cannot be empty in image_gd_get_info() (line 349 of /home/testwww/web/informator/modules/system/image.gd.inc). 
The specified file logo.gif could not be uploaded. Only JPEG, PNG and GIF images are allowed.  


It happens even though I have the paths in Configuration > Media > File System set to be inside the web root. 


Public file system path: sites/[my directory]/files [permission 775]
Temporary directory: sites/[my directory]/files/tmp [permission 755]


It seems that Drupal tries to save a temporary file in /tmp/ although the temporary directory is set to something different. 

How can I fix the problem to be able to upload a file?
The key here is that PHP is attempting to create the temporary file in a public directory. If you refer to the your PHP settings, find out what is specified for the 'upload_tmp_dir'. Use a phpinfo() call to display this, also available in the Status Report by clicking on the PHP version number. This directory has special privileges that open_basedir will not block. Set your drupal temp directory to this path explicitly and it should work.