Trying to create a server with port forward and on CMD it comes up with
"Error: Could not find or load main class @libraries.net.minecraftforge.forge.1.18.1-39.0.88.win_args.txt"

I had the same error but for Linux on my server. I fixed it by applying the rights for the user to read as also write and execution permission on the server folder. Make sure your path is right and the file exists.
Than every thing is supposed to work.
Maybe you can upgrade the modpack and the error will go away too.

I was getting a similar error same message just different version numbers. I installed Java 17 that seems to have fixed the issue for me. I saw a reddit thread that mentioned something about needing java 17 for minecraft servers 1.18 and above, not sure how true is but it solved this issue for me.