Thre could be two other things that I can think of:
Permissions maybe: Try “sudo chmod +x /path/yourscript.sh” to make your script explicitly executable.
Also, the environment of cron doing something may be different from when you do it as root or user. So you should always use the full path to every command in your script; like “/bin/tar” instead of just “tar”. To find out, where things are, you can use “whereis tar”, and it will tell you, whether it’s in /bin, /usr/bin or elsewhere.