The 64-bit FixPak image misses the 64-bit DB2 utility db2ckrst, which should be
located at $DB2_DIR/bin64 directory. $DB2_DIR is the directory where DB2 is 
installed. If you don't have the file $DB2_DIR/bin/db2ckrst, you don't need
this missing file. Otherwise, get the file from bin64 directory here and put
it under $DB2_DIR/bin64.