Site crashes after attempt to install webprofiler module with proc_functions disabled in PHP

Edited title: Site crashes after attempt to install webprofiler module with proc_functions disabled in PHP.

I tried to install the devel modules and after each install my site crashes and i can only get a HTTP-error 500.

I have to restore my database to get the site working again.
When i install each module separately, they all work, until i install the last one, the webprofiler, then the crash occurs.

I got the following errormessages out of my DB, watchdog-table:

After the install the last errormessage is:
a:5:{s:5:"%type";s:52:"Symfony\Component\Process\Exception\RuntimeException";s:8:"@message";s:87:"The Process class relies on proc_open, which is not available on your PHP installation.";s:9:"%function";s:48:"Symfony\Component\Process\Process->__construct()";s:5:"%file";s:84:"/home/pkgnum/domains/onsnuenen.nl/public_html/vendor/symfony/process/Process.php";s:5:"%line";i:144;}

when i go to my site again after this happened, i get the HTTP-error 500. There are 2 errormessages after that in the log:

a:5:{s:5:"%type";s:7:"Warning";s:8:"@message";O:25:"Drupal\Core\Render\Markup":1:{s:9:" * string";s:60:"uasort(): Array was modified by the user comparison function";}s:9:"%function";s:50:"Drupal\shortcut\Entity\ShortcutSet->getShortcuts()";s:5:"%file";s:98:"/home/pkgnum/domains/onsnuenen.nl/public_html/core/modules/shortcut/src/Entity/ShortcutSet.php";s:5:"%line";i:120;}

and
a:5:{s:5:"%type";s:52:"Symfony\Component\Process\Exception\RuntimeException";s:8:"@message";s:87:"The Process class relies on proc_open, which is not available on your PHP installation.";s:9:"%function";s:48:"Symfony\Component\Process\Process->__construct()";s:5:"%file";s:84:"/home/pkgnum/domains/onsnuenen.nl/public_html/vendor/symfony/process/Process.php";s:5:"%line";i:144;}

Any ideas what i am doing wrong? Do you need more information, let me know.

Erwin van Maasakkers