err in save data:null

Hi

Im seing the following error keep repeated in the log file. Can someone help me how to identify which device(s) cause this error and which monitor...

09:23:07:174 AM Null obtained for {0} during polling
09:23:08:532 AM err in save data:null
09:23:08:532 AM err in save data:null
09:23:41:049 AM err in save data:null
09:23:41:049 AM err in save data:null
09:23:41:049 AM err in save data:null
09:24:02:649 AM err in save data:null
09:24:02:649 AM err in save data:null
09:24:02:649 AM err in save data:null
09:24:18:705 AM err in save data:null
09:24:19:314 AM Can't Proceed Since a Divide by Zero Operation attempted
09:24:19:314 AM Null obtained while calculating expression OID
09:24:19:314 AM Can't Proceed Since a Divide by Zero Operation attempted
09:24:19:314 AM Null obtained while calculating expression OID
09:24:54:064 AM err in save data:null
09:24:54:064 AM err in save data:null
09:24:54:064 AM err in save data:null
09:24:54:064 AM err in save data:null