%1 must be a non-reference-modified LINKAGE SECTION item whose level number is 01 or 77.
30
Cause . . . . . : You can determine the address of an item defined in the LINKAGE SECTION of a program, provided it is not reference-modified and its level-number is 01 or 77.
Recovery . . . : Change the level-number of the item or assure it is defined in the LINKAGE SECTION.