unable to execute phantomjs from within my CI3 app

I am using koolreport. Koolreport is trying to run phantomjs but it fails with this error:
Type: Exception
Message: Could not execute phantomjs
Filename: /app/vendor/koolreport/export/Handler.php
Line Number: 67

My application is using Docker. Koolreport techS told me to try to run the example code that comes with phantomjs. I did this from the CLI and it runs fine. I have also tried changing the permissions of the phantomjs file. But the files is not found. 
ubuntu@ip-172-31-66-201:~/rst/RST/app/vendor/koolreport/export/bin$ sudo chmod +x app/vendor/koolreport/export/bin/phantomjs

chmod: cannot access 'app/vendor/koolreport/export/bin/phantomjs': No such file or directory
I know it is there because I can see it. 
ubuntu@ip-172-31-66-201:~/rst/RST/app/vendor/koolreport/export/bin$ ls

phantomjs
Can anyone tell me what is going on?

proof that an old dog can learn new tricks

Your chmod command is wrong. You are in ~/rst/RST/app/vendor/koolreport/export/bin and then you then you try to change permission of a file in app/vendor/koolreport/export/bin/phantomjs. The OS is right, it doesn't exist. Try sudo chmod +x phantomjs.

...but the question remains, since when a javascript file needs to be executable? This doesn't make any sense. It's not a binary file containing an executable program, it's just a text file. I should be readable by the web server, not executable. That's an unnecessary security risk.

Thanks. I ended up adding the path to ~/export/bin to my path and now when I try to run I get the string that should run (see below). And when I run it from the cli I get:

ubuntu@ip-172-31-66-201:~$ phantomjs --ignore-ssl-errors=true /app/vendor/koolreport/export/pdf/pdf.js /tmp/61b9eeb9320de2.tmp /tmp/61b9eeb9322f93.pdf eyJmb3JtYXQiOiJBNCIsIm9yaWVudGF0aW9uIjoicG9ydHJhaXQiLCJleHBlY3RlZExvY2F0aW9uIjoiaHR0cDpcL1wvc3RhZ2luZy5kYXNoYm9hcmQucmVzZWFyY2hzdHVkeW9ubGluZS5jb21cL2luZGV4LnBocFwvQ29uZmlndXJlXC9leGVjdXRpdmVfc3VtbWFyeSIsInJlc291cmNlV2FpdGluZyI6MTAwMH0=
Can't open '/app/vendor/koolreport/export/pdf/pdf.js'

So do I need to add another path?

proof that an old dog can learn new tricks

The path is wrong in your command. According to your previous post, the app folder is in ~/rst/RST/, not in / (the root of the file system). So your command should be something like this: 
phantomjs --ignore-ssl-errors=true ~/rst/RST/app/vendor/koolreport/export/pdf/pdf.js ...