I will try to explain this to you, dear -midnight, so you can also enjoy HIPS and understand what it does and better even what it does not do for the Avast user.
All technical issues can also be explained in a way to inexperienced netizens, so they might grow in their experience and may enjoy their gained insights in a proper way. So shall we give this a try, as you already came a long way after you joined the official avast user forums, and I bear witness of this.
It is a warning that Avast has not seen this software run before, you can allow it when you know that it is above board. What were you doing exactly just before or during that this HIPS alert appeared? You could say I was updating a program I checked before but Avast has never seen it.
Avast HIPs does this for first time when a particular new program or program update is run or is to run. When Avast HIPS has established it as OK, it will be further left to run without a second alert.
The above extra security procedure is an additional security measure, like when you get a PUP alerrt when you have set avast to alert for PUPs (not set as by default).
I have the PUP alert set for ON, because I do not like potential unwanted programs (adware for instance).
I would keep HIPs and come to get familiar with the workings thereof, which is not too complicated when you are given the A to Z to work it right. Another lesson learned, another insight gained, and so we learn everyday, isn't it.
polonus