When using the Merge Contacts function of the Notes Migrator for Exchange, this error is seen in the log file and indicates that the tool is unable to match the Target Address values.
This error may occur when the forwarding "Target Address" has been set on the AD User Security Objects and does not match the Target Address which is set on the Contact Objects.
To check the Target Address of the AD User Security Object do the following:
Open ADSIEDT.MSC from Start/Run
Locate the User Object and then open the properties
Look for the Attribute named "Target Address" - if this value is set, please verify that it matches the same value on the Contact Object.
As a resolution:
Either remove the "Target Address" values on the User Objects or change them to match the values on the Contact Objects.