Issue with Indentation

Hi all,

Today will be my worst day working on Sikuli. For some reasons, the simple codes below keeping complaining the error :

[error]Stopped
[error]Error message: IndentitationError:('unindent does not match any outer indentation level',...........py',15,12,'sleep(1)\n

Below are my codes :

CountryFile = open('c:\\temp\\test1.txt')
SourceFile = open('c:\\temp\\test2.txt')

while 1:
    NewCtyCode = CountryFile.readline()
    if not NewCtyCode:
        break

    while 2:
        DetailLine = SourceFile.readline()

        if not DetailLine:
            break
        if exists("3Cratrule.png"):click("3Cratrule.png")
        if exists("1333424884373.png"): <------- if i remove this line and below, everything is fine.
            sleep(1)

If i change the last 2 lines to :
        if exists("1333424884373.png"): sleep(1) <--- this give me "mismatched input" expecting DEDENT

I had double check all the syntax and indentation, but it seems very fine to me.

Any advise ?

Thanks in advance.