The compiler can't read the parameter value of the opcode 05B6, or the value is not a number.
This opcode references a chunk of debug data left by the game developers. This data is cached in *.bin files in the Sanny Builder directory. It has no special meaning in runtime and is left in the disassembled code only to preserve one-to-one match with the original script.
Since v3.6 Sanny Builder deprecates the old form of this opcode with a single number parameter in favor of the new ktype. Now this instruction accepts a string literal enclosed in double quotes:
05B6: 1 // before v3.6
05B6: "some string" // after v3.6
Similar opcodes in SA Mobile have been updated too:
0A66: write_log "Mission Page 0"
0A67: write_log_int 15@ 15@ 15@ "taking money off player"