Should the following message be displayed within Salesforce when attempting to use the "Find Company" function via the "Business Intelligence - Lead View" Visualforce Page then it indicates that no Lead Field have been mapped within the "Find Company Options" under the "Application Options" tab of the applications "Configuration" UI:

In order to resolve the issue, please ask your Salesforce System Administrator to map a Lead Field to either the "Company Name" or "Registration Number" Field within the applications "Configuration" by performing the following:

Business Intelligence > Configuration > Application Options > Find Company Options > Lead

Once a Lead Field has been selected / mapped from the drop-down and the configuration saved the message should no longer be displayed.