problems with tkinter updates

[woooee]

if line is not None: probably does not work the way you expect.  You
might try
if line.strip():
Take a look at this quick example

test_lines = ["Number 1\n", "\n", ""]
for ctr, line in enumerate(test_lines):
    print ctr, line
    if line is not None:
         print "     not None"