just unpacked on the server and this error is the first thing I see. I created zp-data and touched debug.log with 775, PHP 5, my own host. Any ideas?

Warning: fopen(/var/www/clients/zp-data/debug.log): failed to open stream: Permission denied in /var/www/clients/zp-core/setup/setup-primitive.php on line 122 Warning: fwrite() expects parameter 1 to be resource, boolean given in /var/www/clients/zp-core/setup/setup-primitive.php on line 123 Warning: fclose() expects parameter 1 to be resource, boolean given in /var/www/clients/zp-core/setup/setup-primitive.php on line 124 Warning: fopen(/var/www/clients/zp-data/debug.log): failed to open stream: Permission denied in /var/www/clients/zp-core/setup/setup-primitive.php on line 122 Warning: fwrite() expects parameter 1 to be resource, boolean given in /var/www/clients/zp-core/setup/setup-primitive.php on line 123 Warning: fclose() expects parameter 1 to be resource, boolean given in /var/www/clients/zp-core/setup/setup-primitive.php on line 124 Warning: fopen(/var/www/clients/zp-data/debug.log): failed to open stream: Permission denied in /var/www/clients/zp-core/setup/setup-primitive.php on line 122 Warning: fwrite() expects parameter 1 to be resource, boolean given in /var/www/clients/zp-core/setup/setup-primitive.php on line 123 Warning: fclose() expects parameter 1 to be resource, boolean given in /var/www/clients/zp-core/setup/setup-primitive.php on line 124

This is an indication of a file permissions error on your server. The server must be configured to allow Zenphoto to write/create files that are in the zp-data folder of the installation.

So, check the folder permissions of the zp-data folder. You can also try deleting the debug.log file. Zenphoto will re-create it as needed. Maybe then the file permissions will "pass".

Look for any other errors in your logs, though. Zenphoto probably would not be writing to the debug log unless it encountered some other problem. (Could, of course, be the same permission issue on some other file.)