Error messages at syslog.log related to disk

Hi,

Many error messages in my server running hp-ux 11.11 related to writing to disk.

Sep 29 08:50:00 prod4 vmunix: Synchronous Page I/O error occurred while paging to/from disk

Sep 29 08:50:00 prod4 vmunix: device 0x4000000a, 1K block #38120, 4096 bytes of 4096 bytes not paged, page addr =7f10c00.6e1df000,  bflag =1f, bp = 8adebcc0

Sep 29 08:50:00 prod4 vmunix: Page I/O error(1) while swapping from disk for device 0xffffffff,

Sep 29 08:50:00 prod4 vmunix:   block #33849658, page addr = 7f10c00.6e1df000

Sep 29 08:50:00 prod4 vmunix: Making a range of swap blocks unavailable for future use. Please check

Sep 29 08:50:00 prod4 vmunix: for any possible hardware/firmware errors on the swap

Sep 29 08:50:00 prod4 vmunix: device IMMEDIATELY

thanks for your help.