After QCad-2.0.4.0-r3 had built I noticed it said it was setting permissions. When the program was fully installed I ran the program and it started fine giving me the first time start up unit setting request. This continued to appear on subsequent runs. I was unable to make permenant changes to the settings. Qt reported "QQSettings::sync: filename is null/empty." Some investigation showed the config file should be "~/.qt/qcadrc". I do not believe I had a "~/.qt" directory before the install. I tried to make an empty file and could not. I did "ls -ld ~/.qt" and found it belonged to root:root. I changed the ownership to match my user account and QCad was now able to create and save it's settings correctly.
I can reproduce this problem with the qcad version presently in portage hence I am closing this bug for now. Please re-open if this is still an issue for you. Thanks, Markus