Thanks a lot @caitlinadams. I am sure the GAMMA module needs a refresh. I haven't worked with it for about two years and pyroSAR does not support the latest versions. We have recently obtained a new version and so I will also update pyroSAR to be able to use it. Another related issue is #313 opened by a colleague of mine.

So, you are very welcome to provide the fix you suggest above if you find the time. I agree with your suggestion. However, I could imagine that you run into more errors after this.
I will look into it next week. Once I've opened a PR I will ask you for feedback? Sounds good?
What version (release date) of GAMMA are you using and which modules do you have available?

No problem, @johntruckenbrodt -- I'm happy to collaborate on the refresh as I can while getting pyroSAR working with our GAMMA version. In the end, I figured out that GAMMA couldn't find some key shared objects for FFTW3 and GDAL, and we solved the import errors by creating symlinks to those objects on our supercomputer. Specifically, the issue was that we couldn't actually run the gamma binaries:

[~]$ GAMMA_SOFTWARE-20230712/DISP/bin/data2geotiff
GAMMA_SOFTWARE-20230712/DISP/bin/data2geotiff: error while loading shared libraries: libgdal.so.20: cannot open shared object file: No such file or directory

If this error had been surfaced by pyroSAR, it would have really helped us with debugging, so perhaps its a matter of displaying any unresolved errors to the user? I found the following code helpful with my debugging, which basically can be used to test if the binary can be run (the output should contain a usage statement if it worked):

from spatialist.ancillary import finder
import re
import subprocess as sp

for module in finder(GAMMA_HOME_PATH, ['[A-Z]*'], foldermode=2):
    print(module)
    for submodule in ['bin', 'scripts']:
        print(f"{module}/{submodule}")
        for cmd in sorted(finder(module+"/"+submodule, [r'^\w+$'], regex=True), key=lambda s: s.lower()):
            command_base = os.path.basename(cmd)
            proc = sp.Popen(command, stdin=sp.PIPE, stdout=sp.PIPE, stderr=sp.PIPE, universal_newlines=True)
            out, err = proc.communicate()
            out += err
            usage = re.search('usage:.*(?=\n)', out)
            if usage is None:
                print("    " + err)
        print("\n\n")

We're using GAMMA_SOFTWARE-20230712 and have DIFF, DISP, ISP, LAT, MSP.

Thanks Caitlin, that's a very good point. These issues with the shared objects are common and it sure would be good to forward any errors to pyroSAR. The parser raises an error when a GAMMA command raises an error but this error is caught in pyroSAR.parser.parse_module. So I guess what happened is that none of the commands in disp could be parsed and thus the whole Python file was not created. You likely didn't notice this during parsing because this function just logs an info message that some commands could not be parsed and displaying logging messages is not turned on by default. See Logging.
I admit this is not really good practice and this kind of information must be made available to the user in any case.