When you are seeing forwarding from Notes to Exchange, you may se the the following error:
"Unable to set forwarding for user 'User Name'. Person document is read-only".
The reason for this is due to the fact that the notes.id specified during running the Notes Functions to set forwarding does not have sufficient rights to update the Notes forwarding address.
Re-run the process making sure that the Notes Administrator account is used
1- Locate the source NABs (Domino names.nsf ) selected in the tool
2- Assign Manager Access with all the roles are checked