Can't create a file with current date

For the life of me I can't seem to get the current date + time + log.txt to work when I try to create a file..

I just want the created file to be named "mm/dd/yyyy-hr:mm:seconds-log.txt

This is my code:

$_filename = @MON & "/" & @MDAY & "/" & @YEAR & "-" & @HOUR & ":" & @MIN & ":" & @SEC & "-log.txt"
;MsgBox(1, "date", $_filename)
$_file = FileOpen($_filename, 2)
If $_file == -1 Then
    MsgBox(4096, "Critical Error", "Couldn't Create Log File!")
    exit
Endif

I first tried _Now() and _NowDate() and _NowTime(), They all set the variable to the date and time + log.txt but when I try to create the file it throws the error msg EVERYTIME!!!

Where is my error?