Dann untersuche den HTTP-Datenverkehr, bspw. mit Firebug, um brauchbarere Infos zu bekommen, als "eine weiße Seite".
ALso ich hab Live HTTP Headers.
Ich sehe da nichts unnormales:
http://example.com/Login/Formular
POST /Auth/Login HTTP/1.1
Host: example.com
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 3.5.30729)
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Referer: http://example.com/
Cookie: PHPSESSID=1d6c966a70778e6dba4d3c920e81622d; __utma=266937500.1663667665.1253201419.1253201419.1253218060.2; __utmc=266937500; __utmz=266937500.1253201419.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __utmb=266937500.7.10.1253218060
Content-Type: application/x-www-form-urlencoded
Content-Length: 49
loginName=test&loginPw=test&ref=%2F&Login=Login
HTTP/1.x 200 OK
Date: Thu, 17 Sep 2009 20:15:01 GMT
Server: Apache/2.2.9 (Debian)
X-UD-Host: webspace.udag.de
X-UD-Method: urlhiding
X-UD-Target: http://example.com/
X-UD-Loopcounter: 2
X-UD-REMOTE_ADDR: 91.57.204.14
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Vary: Accept-Encoding
Set-Cookie: USERAUTH=c522e1c1aeefcace6671f16d96aaded0; path=/; httponly
Content-Encoding: gzip
Content-Length: 20
Keep-Alive: timeout=15, max=97
Connection: Keep-Alive
Content-Type: text/html; charset=utf-8
Grüße, phil