Hi,
I am trying to get Zen installed on my domain but cannot get the installation wizard to appear
Checked permissions on files and folders, seems OK

When I navigate to
http://www.mydomain.be/zen/zp-core/setup.php

The errors I get are:
Warning: copy(.../public_html/zen/.htaccess) [function.copy]: failed to open stream: Permission denied in ../public_html/zen/zp-core/setup.php on line 265

Warning: fopen(.../public_html/zen/zp-data/setup_log.txt) [function.fopen]: failed to open stream: Permission denied in /.../public_html/zen/zp-core/setup/setup-functions.php on line 341

Warning: Cannot modify header information - headers already sent by (output started at .../public_html/zen/zp-core/setup.php:265) in .../public_html/zen/zp-core/setup.php on line 298

Error!

Setup was not able to create this file. You will need to edit the zp-config.php.source file as indicated in the file's comments and rename it to zp-config.php. Place the file in the zp-data folder.

You can find the file in the "zp-core" directory.

Warning: fopen(.../public_html/zen/zp-data/setup_log.txt) [function.fopen]: failed to open stream: Permission denied in .../public_html/zen/zp-core/setup/setup-functions.php on line 341

Fatal error: Call to undefined function db_connect() in .../public_html/zen/zp-core/setup.php on line 779

As the error tells you check the file/folder permissions. Please visit the troubleshooting guide for info about how to set these manually.

Checked the the troubleshooting guide and all folders have 755 and files have 644 as instructed
I am reluctant to put everything to 777
Please advise

Give 0777 a try. If it works, complain to your ISP that their configurations are bad. I personally would not want to run at 0777 on a publicly accessable site, but if that is all that works, you have to either run that way, get the ISP to fix its problems, or change ISP.

Have put entire folder structure (all files and folders) on 777
Still unable to get this working, disappointment.

How shall I address this to my ISP.
What do they need to change? Any suggestions on that?

Tell them what you told us. Maybe point them even to your setup file so they see it or this thread.

create a htaccess before the setup with

AddHandler x-httpd-php53 .php

I am actually not sure how this would help with wrong set permissions...

i had exactly the same errors and with this fix all the errors were gone

Ok, but that htaccess just allows php file types, doesn't it ? That normally does not fix wrong permission. But whatever helps...:-)