Because those are not proper S7 STL statements.

The code uploaded from a PLC is damaged by a programmer's mistake.

Hello Manass;

From the code snippet you provided us with, it looks like you are trying to program indirect addressing through pointers, with a S7-300 or S7-400 CPU.

In STL, this would require you use the LOAD (L) instruction, with a  pointer (P) as argument. 

Thiw would look like this : L  P# x.y, where x is a byte address and y is a bit address (inside that byte) to identify the pointer value (bit) that you want to transfer to ACCU1.

Look at the attached screenshot below, taken from the Statement List (STL) for S7-300 and S7-400 manual. You can download the manual here:

https://support.industry.siemens.com/cs/ww/en/view/109751814

Hope this helps,

Daniel Chartier