The individual file:
C:\WINNT\system32\dhcp\tmp.edb
...is safe to exclude from backups, and/or ignore from error reports. The DHCP database gets secured along with the System_State (or Shadow_Copy_Components). Also, DHCP backs itself up once every hour to a separate "/backup" folder anyway, and unless you explicity exclude this folder from your file system backups, then your backups will secure this "/backup" of DHCP too.