A significant part of sql server process memory has been paged out

hello..
      Last  2days back , one of my sqlserver raise a error messages like
05/24/2011 05:56:18,spid1s,Unknown,A significant part of sql server process memory has been paged out. This may result in a performance degradation. Duration: 14431 seconds. Working set (KB): 12452<c/> committed (KB): 32228<c/> memory utilization: 38%. 05/24/2011 03:56:36,spid1s,Unknown,A significant part of sql server process memory has been paged out. This may result in a performance degradation. Duration: 7248 seconds. Working set (KB): 12528<c/> committed (KB): 32484<c/> memory utilization: 38%. 05/24/2011 02:56:46,spid1s,Unknown,A significant part of sql server process memory has been paged out. This may result in a performance degradation. Duration: 3658 seconds. Working set (KB): 12544<c/> committed (KB): 32228<c/> memory utilization: 38%. 05/24/2011 02:25:49,spid1s,Unknown,A significant part ...