How to reproduce:
1. Create a new Unity project
2. Import a shortcut(.lnk file) to a path outside of the project
3. Select Help > Report a Bug
4. Fill out the bug report form and click 'Send'

Expected result: packing ignores the shortcut path
Actual result: packing does not ignore the shortcut path and throws an error

Reproducible with: 2017.4.29f1, 2018.4.2f1, 2019.1.7f1, 2019.2.0b6, 2019.3.0a6

Notes:
Make sure the shortcut path contains at least one file
Could not reproduce with shortcuts to files, only with shortcuts to folders