Well I would never have thought of it, but Les was spot on with his diagnosis. It would appear that one or more of the computers in your list either had a leading space or a trailing space. I added some trailing spaces to my list of computers and got the same error you did. By adding the code below it then ran correctly again.

Thanks Les

By adding this, it removes any of those spaces in the file
(though it's better if you didn't have spaces in the first place)
$sComputer = Trim($sComputer)

 
Try this code out now and hopefully it should work correctly on your whole list. Then you can start working on logging it.
 
Break On
Dim $SO
$SO=SetOption('Explicit','On')
$SO=SetOption('NoVarsInStrings','On')
$SO=SetOption('NoMacrosInStrings','On')
 
Dim $sComputers,$sComputer,$Details,$Detail
Dim $Alive,$WMIOkay,$CleanUp
$sComputers = ReadFile(@ScriptDir+'\'+'computer_list.txt')
For Each $sComputer In $sComputers
  $sComputer = Trim($sComputer)
  If $sComputer
    $Alive = Ping($sComputer)
    If $Alive
      $WMIOkay = ConfirmWMI($sComputer)
      If $WMIOkay
        $Details = GetBIOSInfo($sComputer)
        For Each $Detail In $Details
          If $Detail
            'BIOS for ' +$sComputer +': ' + $Detail ?
          EndIf
        Next
      EndIf
    EndIf
  EndIf
  ??
Next
 
Function GetBIOSInfo(optional $sComputer)
  Dim $WMIService,$BIOSItems,$BIOSName,$BIOSVersion,$SMBIOSVersion
  Dim $Item, $SerialNumber, $Manufacturer, $BIOSArray[4]
  $sComputer=IIf(Not $sComputer,'','\\'+Join(Split($sComputer,'\'),'',3)+'\')
  $WMIService = GetObject('winmgmts:{impersonationLevel=impersonate}!'+$sComputer+'root\cimv2')
  $BIOSItems  = $WMIService.ExecQuery('Select * from Win32_BIOS where PrimaryBIOS = true',,48)
  For Each $Item in $BIOSItems
    If $Item
      $BIOSName      = Trim($Item.Name)
      $BIOSVersion   = Trim($Item.Version)
      $SMBIOSVersion = Trim($Item.SMBIOSBIOSVersion)
      $SerialNumber  = Trim($Item.SerialNumber)
      $Manufacturer  = Trim($Item.Manufacturer)
    EndIf
  Next
  $BIOSArray[0]=$BIOSName $BIOSArray[1]=$BIOSVersion $BIOSArray[2]=$SMBIOSVersion $BIOSArray[3]=$SerialNumber
  $BIOSArray[4]=$Manufacturer
  $GetBIOSInfo=$BIOSArray
EndFunction
 
Function ReadFile($file)
  Dim $lf, $f, $_, $t
  $lf=CHR(10)
  $f=FreeFileHandle
  $_=Open($f,$file)
    If @ERROR Exit @ERROR EndIf
    Do $t=$t+$lf+ReadLine($f) Until @ERROR
    $_=Close($f)
  $ReadFile=Split(SubStr($t,2),$lf)
EndFunction
 
Function Ping($sComputer)
  Shell'%comspec% /c ping -n 1 '+$sComputer+' >nul'
  $Ping = NOT @ERROR
EndFunction
 
Function ConfirmWMI(optional $sComputer)
  Dim $objWMIService,$objWMISetting,$colWMISettings
  $sComputer=IIf(Not $sComputer,'','\\'+Join(Split($sComputer,'\'),'',3)+'\')
  $objWMIService  = GetObject('winmgmts:{impersonationLevel=impersonate}!'+$sComputer+'root\cimv2')
  If @ERROR
    $ConfirmWMI = Val('&'+Right(DecToHex(@ERROR),4))
    Exit $ConfirmWMI
  EndIf
  $colWMISettings = $objWMIService.ExecQuery('Select * from Win32_WMISetting')
  For Each $objWMISetting In $colWMISettings
    $ConfirmWMI = $objWMISetting.BuildVersion
  Next
  Exit $ConfirmWMI
EndFunction