I can file a bug report.
Just wanted to add something I forgot to mention and make sure it is still a bug.
If I leave the field "parent" within skin.properties empty the error occurs.
If I explicitly add flamingo "parent=flamingo" the error does not occur.
 From the description in the documentation I assumed it
is not necessary to add the parent because it is defined in
"xwiki.defaultbaseskin" within "xwiki.cfg". 
Is it a bug or a feature?
Regards,
sthag
Am 02.05.2017 15:20:52 schrieb Thomas Mortagne <thomas.mortagne(a)xwiki.com>om>:
Looks like a bug to me. Would be great if you could create an issue on
 and detail the steps to reproduce it.
On Tue, May 2, 2017 at 2:50 PM, Interaktionsweise
wrote:
  Hi,
 I tried two skins with the same edits.
 I only changed the file companylogo.vm and added a file logo-company.png.
 The skin.properties file points to flamingo as parent.
 In one skin folder I copied all of the flamingo files and edited as described.
 If I change the skin for the wiki everything is as expected and the changes show up with
the newly set skin.
 The other skin folder only has the edited files
 _ companylogo.vm
 _ logo-company.png
 _ skin.properties
 If I switch to this skin, tested changing it only for one page, I see an error "You
are not allowed to view this page or perform this action" after pressing save.
 If I try to switch to the changed page from the wiki frontend, I only see a blank page.
 Is there something I'm doing wrong? Why is there no inheritance?
 Regards,
 sthag
 Interaktionsweise [
https://interaktionsweise.de] ยท neues(a)interaktionsweise.de
[mailto:neues@interaktionsweise.de]
 Am 02.05.2017 10:32:23 schrieb Thomas Mortagne :
 On Tue, May 2, 2017 at 9:55 AM, Interaktionsweise
 wrote:
  Hi,
 I'm trying to create a new skin. I followed the section Skins within the
Developer's Guide and also Platform Features / Skins.
 The article "How to create a new skin" says to copy the whole colibri (should
be flamingo by now) skin folder and make an example change. Then there is a part about
skin.properties. The property "parent" indicates a skin to inherit from. It says
that it always has a value, even if I don't explicitly enter one for myself it will
inherit from WAR or whatever is configured in "xwiki.defaultbaseskin". 
  Does that mean I don't have to copy the whole
flamingo folder if I reference flamingo as "parent"? This way I could only
create a custom named folder within the xwiki/skins folder with the skin.properties file
and for example a logo.png file which would replace the flamingo logo.png file. 
 Yes you can inherit from Flamingo, no need to duplicate it if you just
 want to customize some templates only.
  I don't understand the behavior and the
functionality of this inheriting and parent child relation of skins from the articles in
the documentation. Why have a parent if I copy the whole skin folder anyways?
 Regards,
 sthag 
 --
 Thomas Mortagne