The object you're trying to use is open by some one/thing else - maybe Windows crashed, or you restarted something while it was busy?
In the version 5.2.11 the error occur @ time of booting.
Error: 0xe0050043 Data store object attribute is open
No article in KB also.
sounds like SBFS corruption - eboot the machine and it should repair. You should see errors in the client log as well.