I am experiencing a similar problem.
Here is a log fragment. I can provide a full log file if it helps.
7:27:07 AM--nsGMailPOP.js - loginOnloadHandler - aRedirect <meta http-
equiv="refresh" content="0; url='
http://mail.google.com/mail/?
ui=html&amp;zy=l&auth=DQAAAHgAAAAPGko2CmH0LH0E6Ohl1B0K6ajl-
qSq87Hd5GocIpeYGLq2Aew2l5tbh1quflvt0d_20z9ylDU554DNPTs5KPlSTOVjBaHdxCjt9QPJr8Fhrd9_xRf8L6kLYhvr5ptNhXZs4hh_GLlkOr3BYEQR8NgH4EWXxZQO9Tc9nZk0RTNKqQ&gausr=<username>
%
40gmail.com'">,'
http://mail.google.com/mail/?
ui=html&amp;zy=l&auth=DQAAAHgAAAAPGko2CmH0LH0E6Ohl1B0K6ajl-
qSq87Hd5GocIpeYGLq2Aew2l5tbh1quflvt0d_20z9ylDU554DNPTs5KPlSTOVjBaHdxCjt9QPJr8Fhrd9_xRf8L6kLYhvr5ptNhXZs4hh_GLlkOr3BYEQR8NgH4EWXxZQO9Tc9nZk0RTNKqQ&gausr=<username>
%
40gmail.com'
7:27:07 AM--nsGMailPOP.js - loginOnloadHandler - redirectURL
'
http://mail.google.com/mail/?
ui=html&zy=l&auth=DQAAAHgAAAAPGko2CmH0LH0E6Ohl1B0K6ajl-
qSq87Hd5GocIpeYGLq2Aew2l5tbh1quflvt0d_20z9ylDU554DNPTs5KPlSTOVjBaHdxCjt9QPJr8Fhrd9_xRf8L6kLYhvr5ptNhXZs4hh_GLlkOr3BYEQR8NgH4EWXxZQO9Tc9nZk0RTNKqQ&gausr=<username>
%
40gmail.com'
7:27:07 AM--HttpComms3.js - setURI - '
http://mail.google.com/mail/?
ui=html&zy=l&auth=DQAAAHgAAAAPGko2CmH0LH0E6Ohl1B0K6ajl-
qSq87Hd5GocIpeYGLq2Aew2l5tbh1quflvt0d_20z9ylDU554DNPTs5KPlSTOVjBaHdxCjt9QPJr8Fhrd9_xRf8L6kLYhvr5ptNhXZs4hh_GLlkOr3BYEQR8NgH4EWXxZQO9Tc9nZk0RTNKqQ&gausr=<username>
%
40gmail.com'
7:27:07 AM--HttpComms3.js - setURI - invlaid url
7:27:07 AM--HttpComms3.js - requestMethod - GET
7:27:07 AM--HttpComms3.js - send - START
7:27:07 AM--HttpComms3.js: send : Exception :
NS_ERROR_INVALID_POINTER.
Error message: Component returned failure code: 0x80004003
(NS_ERROR_INVALID_POINTER) [nsIIOService.newChannelFromURI]
342
7:27:07 AM--nsGMailPOP.js: loginHandler : Exception : Error.
Error message: httpConnection returned false
7:27:07 AM--nsGMailPOP.js - serverComms - START
7:27:07 AM--nsGMailPOP.js - serverComms msg -ERR negative vibes (GMail)