kernel.asm:60: error: comma, colon, decorator or end of line expected after operand

Question

So I'm writing my own 16-bit operating system kernel and i get this error: kernel.asm:60: error: comma, colon, decorator or end of line expected after operand and I don't know why. Here is the code:

; 16-bit registers: ax, bx, cx, dx, si, di, sp, bp
; BIOS interrupts: 0x10, 0x16, 0x13
; Hex numbers: 0A, 20, 3E, 5B, 5D

org 0x8000
BITS 16

%define LNE 0x0A 
%define PROMPT db 'asdasdaOS >', 0

section .data
    buffer resb 65  ; Reserve space for command buffer (+1 for null terminator)

    help_cmd db 'Available commands:', LNE, 'help - display this help command', LNE, 'version - display OS version', LNE, 0
    version_cmd db 'asdasdaOS version 0.0.1 alpha', LNE, 0

section .text

global _start

    _start:
        jmp main

    puts:
        ; save registers we will modify
        pusha

    .loop:
        lodsb                 ; Load next character from string into AL
        or al, al             ; Check if AL is null (end of string)
        jz .done              ; If zero, end of string

        mov ah, 0x0E          ; BIOS teletype output
        mov bh, 0             ; Page number
        int 0x10              ; Call video service BIOS interrupt

        jmp .loop

    .done:
        ; Restore registers
        popa
        ret

    main:
        ; Set up data segments
        mov ax, 0             ; DS and ES cannot be set directly in 16-bit mode
        mov ds, ax
        mov es, ax

        ; Set up stack
        mov ss, ax
        mov sp, 0x8000        ; Stack grows downwards from where we are loaded in memory

        ; Print welcome message
        mov si, msg_hello
        call puts

    .get_command:
        ; Print prompt
        mov si, PROMPT < this is where i get my error 
        call puts

        ; Clear buffer
        xor di, di
        mov cx, 64  ; Maximum command length
        mov al, 0
        rep stosb

        ; Read input command
        mov ah, 0x00           ; BIOS keyboard interrupt
        int 0x16               ; Wait for keypress
        cmp al, 0x0D           ; Check if Enter key was pressed
        je .execute_command    ; If Enter, execute command
        mov [buffer + di], al  ; Store character in buffer
        inc di                 ; Move to next buffer position
        call putchar           ; Echo character to screen
        jmp .get_command       ; Repeat until Enter is pressed

    .execute_command:
        ; Null-terminate buffer
        mov byte [buffer + di], 0

        ; Compare buffer with commands
        mov si, buffer
        mov di, help_cmd
        cld                     ; Clear direction flag for string operations
        repe cmpsb              ; Compare buffer with help command
        je .print_help          ; Jump if buffer matches help command

        mov si, buffer
        mov di, version_cmd
        cld
        repe cmpsb
        je .print_version

        ; Unknown command, print error message
        mov si, unknown_cmd_msg
        call puts
        jmp .get_command

    .print_help:
        ; Print help command
        mov si, help_cmd
        call puts
        jmp .next_line

    .print_version:
        ; Print version command
        mov si, version_cmd
        call puts
        jmp .next_line

    .next_line:
        ; Print newline
        mov al, LNE
        call putchar
        jmp .get_command      ; Get next command

    ; Subroutine to print a single character
    putchar:
        mov ah, 0x0E          ; BIOS teletype output
        mov bh, 0             ; Page number
        int 0x10              ; Call video service BIOS interrupt
        ret

    msg_hello: db 'asdasdaOS ver 0.0.1 alpha', LNE, 0
    unknown_cmd_msg: db 'Unknown command', LNE, 0

I tried using nasm -f bin kernel.asm -o kernel.bin. The code doesn't work and if I change mov si, PROMPT with lea si, [PROMPT] I get this and the error mentioned: kernel.asm:60: error: expecting ] at end of memory operand