Leaving the fields empty before saving, it will be OK until attaching a document to the contract, it will then generate the error saving the report.
Fixed in ZENworks Asset Management 7.5 Interim Release 18 or newer
Interim Releases can be scheduled to run automatically or can be downloaded manually at https://download.novell.com. The Interim releases can be set up within the ZAM Manager for the Task server to check the site on a scheduled basis, and download and apply them automatically. Please refer to the Help Section details of how to set up automatic downloads if desired.
Each interim release is cumulative. If Interim Release 18 is not available due to a newer interim release being placed on the website, be assured that the code needed is in the later release.