strace shows that it's trying to talk to /tmp/scim-panel-socket:0-root. It seems to be hard to fool scim about the user name; it uses getuid() rather than the effective user ID (presumably has to in order to support "ordinary" setuid-root X applications), which will always be 0 in ubiquity, and there's no higher-priority override. We might just have to add one.
strace shows that it's trying to talk to /tmp/scim- panel-socket: 0-root. It seems to be hard to fool scim about the user name; it uses getuid() rather than the effective user ID (presumably has to in order to support "ordinary" setuid-root X applications), which will always be 0 in ubiquity, and there's no higher-priority override. We might just have to add one.