Row type of DDIC table type &1 (form level &4) is incorrect

Trados = docu -> fi -> fica -> fica.tmw

What causes this issue?

During the check of table type &1 in form level &V4&, an incorrect
line type
was determined. &V2& was expected, but &V3& was determined.

System Response

The form class is inactive and cannot be used.

How to fix this error?

Activate the form class.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.