The message says:

SQL1390C The environment variable DB2INSTANCE is not defined or is invalid.

and the SQL10007 is also returned because of this – so fix the DB2INSTANCE by setting it to your current instance.

set  DB2INSTANCE=whateveryourinstanceis

Addition: Your driver seetting within DBeaver should point to the correct location of following files: db2java.zip db2jcc_license_cu.jar (or similar) db2jcc4.jar