[bu-users] backup /var/run fails, reports nothing to backup

[jack b. <by...@gm...>]

running bu as root  trying to backup /var
mostly succeeds, but somehow failing completely to backup /var/run

repeated attempts  say nothing to to backup
[root@bootp ~]# /home/byers/pkg/bin/bu -d /rh8b /var/run

Incremental:      on
Backup directory: /rh8b

No new or changed files to back up

but  /var/run still not there under /rh8b
[root@bootp var]# pwd
/rh8b/var
[root@bootp var]# ls
account  crash  db     ftp  lib    lock  named  opt       racoon  tux  yp
cache    cvs    empty  gdm  local  log   nis    preserve  spool   www
[root@bootp var]#

my parent dir /var/run exists and is populated

the error msg of original bu of entire /var
seems to say why it failed, but i dont know what this means:
[root@bootp bu]# cat log.060905-2.errors
mk_parent_directories(): Error: Could not mkdir /rh8b/var.
File exists
[root@bootp bu]#

am I missing something obvious?
what means 'files exists'?  there is no ordinary file 'run' in  /rh8b/var

 advice?
Jack