Code Fixed:
Mode 1:
#include <File.au3>
$file = "c:\yourfile.txt"
FileOpen($file, 0)
For $i = 1 to _FileCountLines($file)
$line = FileReadLine($file, $i)
msgbox(0,'','the line ' & $i & ' is ' & $line)
Next
FileClose($file)
Mode 2:
#include <file.au3>
$file = FileOpen("yourfile.txt", 0)
While 1
$line = FileReadLine($file)
If @error = -1 Then ExitLoop
MsgBox(0,'',$line)
WEnd
FileClose($file)
Mode 3:
#include <Array.au3>
#include <File.au3>
Local $aInput
$file = "yourfile.txt"
_FileReadToArray($file, $aInput)
For $i = 1 to UBound($aInput) -1
MsgBox (0,'',$aInput[$i])
Next
all tested!