i have the same problem :
"If you enter an incorrect username and password, then you just get a blank white page."
my login.php is not changed
error logs :
i get these two errors :
[Fri Oct 7 01:36:34 2005] [error] [client 82.93.156.116] File does not exist: /home/schoolpl/public_html/\xc2\xa0
[Fri Oct 7 01:36:29 2005] [error] [client 82.93.156.116] File does not exist: /home/schoolpl/public_html/{template_url}/images/spacer.gif
however the spacer.gif file is in that directory.
what the first error means i don't know