Picture rejections reasons raise questions.

9168 and 6037: the one owning that site has the right to decline the publication and commercial use of pictures showing their site. There is always an owner, even if you do not know them. And for sure, even if it is "public domain", how should the moderator know that. Adobe needs to protect their customers (and itself) against claims of using assets that were not cleared. But independently from the location, the guy will need a model release, and you will need clearance from Addidas for the shoes (secret revelation: you wont get it, so edit the stripes out!). It's probably the same for the second picture. 

As for 9163, I suppose the white balance is wrong. But it should earn also an IP refusal: 

6054 is not really "verbessert" but "verschlimmbessert". There are obvious prossessing errors, like here: 

You should, instead going for HDR do a more "standard" processing, that leaves the image usable and without a colour tint for the end user.

_DSC9168-HDR-MAX.jpg - I'm not sure whether this was considered an IP rejection because you need a Property Release to post images of someone's property or whether it's because there are some visible logos and book covers in the image. You could edit out some of those logos and labels and resubmit it and see if that works.

_DSC6037 Kopie-MAX.jpg - a model release for the person would be necessary; but this might also be rejected for quality issues due to the underexposed and blownout areas.

_DSC9163-MAX.jpg - There is a bit of chromatic aberration among the branches, but the quality issue might also be the composition. I don't know how this could be used in a commercial project.

_DSC6054-Verbessert-RR-MAX.jpg - there are several blownout areas.