What steps will reproduce the problem?
1. Use a 12-core (2 processors, 6 cores each) machine with Suse 12.1
2. cset shield
3. Error message: [Errno 2] No such file or directory: '/cpusets//cpus'

What is the expected output? What do you see instead?
Expected is that cset returns that shielding is not active (since cpusets were 
not manipulated before and cset itself cannot be used due to this error). 
Instead, the error message is displayed.

What version of the product are you using? On what operating system?
openSuse 12.1

cset --version
cset: Cpuset (cset) 1.5.6

uname -srvmpio
Linux 3.0.12-rt30-1.2-desktop #1 SMP PREEMPT RT Thu Dec 8 10:18:29 CET 2011 
i686 i686 i386 GNU/Linux

Please provide any additional information below.

Instead of lying at /cpusets/cpus (e.g. Suse 11.2), the file is now at 
/cpusets/cpuset.cpus (see below). The cset tool is not able to work with these 
new paths.
Does anyone know when and why this was changed? I didn't find any hints on the 
web.

ll /cpusets (after patching the cset.py, therefore system and tasks are new)
total 0
-rw-r--r-- 1 root root 0 Dec 14 15:57 cgroup.clone_children
--w--w--w- 1 root root 0 Dec 14 15:57 cgroup.event_control
-rw-r--r-- 1 root root 0 Dec 14 15:57 cgroup.procs
-rw-r--r-- 1 root root 0 Dec 14 15:57 cpuset.cpu_exclusive
-rw-r--r-- 1 root root 0 Dec 14 15:57 cpuset.cpus
-rw-r--r-- 1 root root 0 Dec 14 15:57 cpuset.mem_exclusive
-rw-r--r-- 1 root root 0 Dec 14 15:57 cpuset.mem_hardwall
-rw-r--r-- 1 root root 0 Dec 14 15:57 cpuset.memory_migrate
-r--r--r-- 1 root root 0 Dec 14 15:57 cpuset.memory_pressure
-rw-r--r-- 1 root root 0 Dec 14 15:57 cpuset.memory_pressure_enabled
-rw-r--r-- 1 root root 0 Dec 14 15:57 cpuset.memory_spread_page
-rw-r--r-- 1 root root 0 Dec 14 15:57 cpuset.memory_spread_slab
-rw-r--r-- 1 root root 0 Dec 14 15:57 cpuset.mems
-rw-r--r-- 1 root root 0 Dec 14 15:57 cpuset.sched_load_balance
-rw-r--r-- 1 root root 0 Dec 14 15:57 cpuset.sched_relax_domain_level
-rw-r--r-- 1 root root 0 Dec 14 15:57 notify_on_release
-rw-r--r-- 1 root root 0 Dec 14 15:57 release_agent
drwxr-xr-x 2 root root 0 Dec 22 13:31 system
-rw-r--r-- 1 root root 0 Dec 22 14:04 tasks

After I've patched the cset.py file, everything worked fine. It would be nice 
if the cset tool would be extended by a detection logic, which file structure 
is used.

I've attached
- diff of the patched cset.py file
- output of  "cat /proc/cpuinfo"
- debug failure log of "cset shield"