Dear lat9,

Yes, something like this on zc155b
disable_functions
exec,passthru,shell_exec,system exec,passthru,shell_exec,system

How I test error?
For example
If I after instlled
rename some file like this one

/includes/templates/template_default/common/html_header.php
to
/includes/templates/template_default/common/html_header.php(xyz)

This will make the front end be blank white page on ZC 154 or 155b, and general will have a logs files under your installed zen cart folder...

But I also try same server install a fresh new ZC 1.5.4 on it, same result, no logs on the zen carts folder's logs postition.
On general the Zen Cart error logs on all cPanel WHM (60.0.28) will be like this
/home/username/public_html/zc154/logs
But nothing there

So I am 100% sure my server have something wrong.

Guess what the error logs files?
it is on this path
/home/username/logs/username_com.php.error.log

I can see the eRROR
PHP Fatal error: require(): Failed opening required 'includes/templates/template_default/common/html_header.php' (include_path='.:/opt/cpanel/ea-php55/root/usr/share/pear') in /home/username/public_html/test154/index.php on line 43

but if all thing right, above text and log will be there
/home/username/public_html/zc154/logs/xxx_logs
not on
/home/username/logs/username_com.php.error.log

Hope someone who using cPanel WHM can share how to fix this

Thank you.