Table definition &1 is unknown.

What causes this issue?

You referred to definition &V1& to print a table, but this definition
is unknown.

System Response

The system issues an error message.

How to fix this error?

This is probably an internal error. Please contact the SAP hotline and
report the problem.

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.