Infection?

as you have no idea where the OP downloaded the package from.

To the OP - PortableApps.com have never distributed a virus/trojan/malware infected package from their official website or download system.

There are occasional false positives, which is most likely what you have seen. If you check at the bottom of the support page - https://portableapps.com/support - you will find a little information on this, including the addresses of two very powerful online scanners, which you can submit the suspect file to, and they will scan it for you with literally dozens of antivirus systems, which will usually make it clear whether it is just one AV system that is getting it wrong, or whether there is something in the package that may look suspicious (many of the apps here are compressed to save space, which is a technique used by malware, which can sometimes trip up heuristic scanners).

As a general rule, when an AV app says something is suspicious, or generic without naming a specific virus or trojan, then it is one of their wider-targetted-with-less-accuracy rules that has detected it, and, while caution is always wise, it is also worth getting a second opinion (virustotal.com, etc.) before panicing.