A first suspicion could be that the DLL “combit.ListLabel.ConversionTools.x86.dll” is missing or not accessible during PDF export.
Could you check your module directory for this? An overview of the files required for distribution can be found in the file Redist.txt in the List & Label installation directory.
Otherwise, like @Hans_Peter_Reische said, we would like to ask you to open a support case in the support center. Please upload the LOG file in the case. To be able to analyze the crash, please also create a DUMP file.
We can then of course share the cause/solution for all users here in the forum.
Thank you very much.