macOS Cronnix script: only works with Terminal

[wesg]

I posted previously about a problem I was having with my script and FTP. I got that working, but now I've run into a problem where Cronnix - the crontab scheduler GUI - only runs the script properly if I use

chmod a+x /path/to/script

before. I understand that the script needs to be executable, but I can't figure out why this needs to be done over and over again.

I tried putting this into the beginning of the script, but it still doesn't work. With the Terminal, everything works as planned.

Any ideas?