SAP Message 60000 - '&' cannot be interpreted as year

Diagnosis
The value '&V1&' was entered for the construction year. This valuecannot be interpreted as being a year.

System Response
Your entry was not accepted by the system.

Procedure
Enter the construction year in a four figure form. You have to enterthe day, month and year if the construction year is the same as thestart or end date of a building age category in the respectiverepresentative list of rents.