ok, so basically what this '$(dirname "$(readlink -fn "$0")")' does is, that it returns the path of the shell file, without the filename.
if you started './testfolder/test.sh' then MC_PATH would contain './testfolder/'.
You can't just replace 'dirname' without removing the stuff after it, because dirname is a function that works with the returnvalue of readlink. Replacing it with 7sanctums doesn't work, because it isn't a function.
Edit: you also need to remove the $ before, and the brackets around it, because that initiates the execution of a function
You should however be able to replace '$(dirname "$(readlink -fn "$0")")' with your path though. Not sure if it had to be in single quotes, double quotes or no quotes at all though, but that should be easy to find out by trying, or asking google (I might try it a bit later).
As for the 'No such file or directory' error: Again, I can't try it with the actuall server files, as I'm not at home, but I tried placing an empty file called server.properties in my script folder, and it worked. there was no error.
Here's one thing you can try though: after the 'MC_PATH=$(dirname "$(readlink -fn "$0")")' you insert a new line 'echo $MC_PATH'. now when you execute the script it shows you the path it's using, and expecting the server files to be in.
Hope this helps you.