If you see this error message in WSS chances are you have an active reference to custom field type but have not installed the field type. The “/_layouts/mngfield.aspx” page will throw this error in the above scenario. Two possible resolutions:
Microsoft Office SharePoint Server 2007 provides a single, integrated location where employees can efficiently collaborate with team members, find organizational resources, search for experts and corporate information, manage content and workflow, and leverage business insight to make better-informed decisions.
• Collaboration Allow teams to work together effectively, collaborate on and publish documents, maintain task lists, implement workflows, and share information through the use of wikis and blogs.
• Portals Create a personal MySite portal to share information with others and personalize the user experience and content of an enterprise Web site based on the user’s profile.
• Enterprise Search Quickly and easily find people, expertise, and content in business applications.