we have upgraded image on cisco 6509 to 151-1.SY1 from 151-1.SY last week , and we have deleted the 151-1.SY image from the switch , but every day we are getting below alert message
Dec  5 09:20:55: %PFREDUN-SW1-4-BOOTSTRING_INVALID: The bootfile s2t54-adventerprisek9-mz.SPA.151-1.SY1.bin is present on the active supervisor but not on the standby
6509#sh slavebootdisk:
-#- --length-- -----date/time------ path
1     33554432 Apr 18 2013 11:56:18 +01:00 sea_console.dat
2     99763688 Nov 10 2013 15:12:52 +00:00 s2t54-adventerprisek9-mz.SPA.151-1.SY1.bin
3            0 Apr 19 2013 00:16:16 +01:00 call-home
4       546304 Sep 28 2013 02:38:50 +01:00 crashinfo_20130928-023850-GMT
5     33554432 Apr 18 2013 12:20:28 +01:00 sea_log.dat
6     28856320 Apr 18 2013 12:37:26 +01:00 c6500-fpd-pkg.151-1.SY.pkg

827883520 bytes available (196673536 bytes used)

6509#sh bootdisk:
-#- --length-- -----date/time------ path
2     33554432 Apr 18 2013 11:31:30 +01:00 sea_console.dat
3     99763688 Nov 10 2013 15:07:36 +00:00 s2t54-adventerprisek9-mz.SPA.151-1.SY1.bin
4            0 Apr 18 2013 23:55:14 +01:00 call-home
5       548563 Aug 16 2013 04:56:28 +01:00 crashinfo_20130816-035628-UTC
6     33554432 Apr 18 2013 11:54:50 +01:00 sea_log.dat
7     28856320 Apr 18 2013 12:12:56 +01:00 c6500-fpd-pkg.151-1.SY.pkg

828211200 bytes available (196345856 bytes used)