Cannot install extension: chown(): Operation not permitted

[DdotKdot]

Hey,
I try to install a custom extension in EspoCRM v3.7.4. Unfortunately I can't handle this.
After uploading the ZIP-File Espo tells me that the extension is ready to install. I install it and everything seams fine! but in background no files are added and in the extension table in database are no file-pathes.
Log-Files tell me this:

[2015-12-02 09:08:21] Espo.WARNING: E_WARNING: chown(): Operation not permitted {"file":"/var/www/basisbox.local/htdocs/application/Espo/Core/Utils/File/Permission.php","line":392} []
[2015-12-02 09:08:21] Espo.WARNING: E_WARNING: chgrp(): Operation not permitted {"file":"/var/www/basisbox.local/htdocs/application/Espo/Core/Utils/File/Permission.php","line":403} []

So it seems like I can't change the ownership from the added files in code and the files aren't added.
What can I do to fix this problem?
Thank you,
Dennis

[DdotKdot]

In realized that in the data/config.php default permissions are set. I adjust them to the user and the group I need but it didn't helped.
Any other advice?