WbadminUIinBuiltTracing problem

Hello,

I'm using Windows 2008 R2 Foundation SP1 server with some roles running on it. Since yesterday I'm having an issue with Kernel-EventTracing/Admin Event ID 2 error:

"Session "WbadminUIInBuiltTracing" failed to start with the following error: 0xC0000035"

Everytime when I open Windows Server Backup this error logs into Error log. 

I've found this thread http://social.technet.microsoft.com/Forums/windowsserver/en-US/02ac2078-ac0e-48d1-b3db-3f2e76319afb/session-wbadmininbuilttracing-failed-to-start-with-the-following-error-0xc0000035 in which  similar error is descriped (with reply that is harmless error). But it's a different session (WbadminUIBuiltTracing x WbadminBuilTracing) so I'm asking if is this harmless too?

What causes this error? Any ideas?

Thanks!