_wchmod returning error no 121. i.e.ERROR_SEM_TIMEOUT

While using the method _wchmod getting an error 121. i.e. Semaphore Time out period has expired.

I would like to know Under what circumstances this error will be returned.

Used the method like       _wchmod(filename,0);

If this is not the right forum, then direct me to the right forum.

Thanks,