I'm guessing that Malware.Packer.Gen is not really malware.
Your guess is correct.
There are a ton of threads on
this forum (and every other software forum) about the insanely irresponsible practice of antivirus companies throwing these false positives when they encounter files that have been compressed or processed by some packager that they are unsure of.
The giveaway for people in the know is always in the name/label of the malware found.. It's always something like "generic packer" (or in your case "Packer.Gen").
That's code for "I don't know what this is so i'm going to label it as potential malware and scare everyone."
The best practice when you encounter something like that is to do what you are doing -- don't ignore it, don't assume it's a false alarm -- but be skeptical of your antivirus, and investigate as you are doing.
And typically the best thing to do is to upload the program in question to a place like
https://www.virustotal.com/ where it will be scanned with tons of different engines, which will usually confirm that most engines report the program as safe.
