Bugs/issues should be reported on Github if possible.
I also accept bugs per mail: github@JonnyJD.net In the end I will always create an issue at github, so it would be of help if you could open a github account and/or follow the issue there.
Please include the version of isrcsubmit and the platform/operating system you are using.
You should also include how you installed isrcsubmit. There are differenct packages available for download and you might even have used a package manager.
Please include the complete command line you used and the (problematic piece of the) output. Additionally tell me about the disc you were trying when this problem is only related to certain discs.