Ardour crash because of system theme

I have set my general theme in xfce (archlinux) to Clearlooks-phenix.

When I start ardour 4.7.0 I have a lot of messages like this
/usr/share/themes/Clearlooks-Phenix/gtk-2.0/gtkrc:79: error: unexpected identifier ‘reliefstyle’, expected character ‘}’
and Ardour window will not show.

I have tried to delete configuration files, but the problem persists.

I don’t understand, since in another computer, with the same theme, I don’t have problems.