Chapter 6. Exchanging metadata with other products: "Converting MDIS-conforming metadata into a tag language file", page 97. You cannot issue the MDISDGC command from the MS-DOS command prompt. You must issue the MDISDGC command from a DB2 command window. The first sentence of the section, "Converting a tag language file into MDIS-conforming metadata," also says you must issue the DGMDISC command from the MS-DOS command prompt. You must issue the DGMDISC command from a DB2 command window.