We have released a new version of OSS v4.0rc9-999 that fixes the problems with KDE audio. Kindly download and isntall the latest version. You will need to uninstall the previous version by running pkg_delete oss-freebsd-v4.0rc9-999-i386 (or -amd64). THen install the new version.
Kindly download from http://www.opensound.com/download.cgi and inform us of any issues.