I have following entries in the error.log
[Fri Jan 19 20:10:12 2018] [error] [client myIP] PHP Warning:
filesize() [function.filesize]: open_basedir
restriction in effect. File(/tmp/phpE4uQRA) is not within the allowed path(s):
(/var/www/) in /var/www/www.example.com/zenphoto/zp-core/zp-
extensions/quota_manager.php on line 225, referer:
http://example.com/zenphoto/zp-core/admin-upload.php
[Fri Jan 19 20:10:12 2018] [error] [client myIP] PHP Warning:
move_uploaded_file() [function.move-
uploaded-file]: open_basedir restriction in effect. File(/tmp/phpE4uQRA)
is not within the allowed path(s): (/var/www/) in
/var/www/www.example.com/zenphoto/zp-core/zp-
extensions/uploader_http/uploader.php on line 97, referer:
http://example.com/zenphoto/zp-core/admin-upload.php
[Fri Jan 19 20:10:12 2018] [error] [client myIP] PHP Warning: Cannot
modify header information - headers already sent by (output started at
/var/www/www.example.com/zenphoto/zp-core/zp-
extensions/quota_manager.php:225) in
/var/www/www.example.com/zenphoto/zp-core/zp-
extensions/uploader_http/uploader.php on line 120, referer:
http://example.com/zenphoto/zp-core/admin-upload.php
Is it possible that you "re-program" ZPC in that way that ZPC does not ask for access outside the webroot.
Like eg. /var/www/www.example.com/zenphoto/tmp/