Hi Jaktard,
To what device are you packaging for and do you have the correct certifications and provisions installed for that device?
Before packaging, right-click on the Contents folder select fix up redirectors in folder. Run a map check for every level map.
If all of these still do not wok, you can download the debugging tools by navigating to the library tab, clicking on the yellow down arrow on the desired engine version and choosing "Options> Editor Symbols for Debugging.
If the steps above don’t help resolve the issue, please open your Output Log and cut and paste contents into a text file and post here.
Thanks,
.