Tomcat and Proxy problems

[Michael Alten <M....@algovision.com>]

Hello,
I'm a novice user to tomcat 3.2.1 and have a problem with the
proxy-settings of a user-domain, which is connected to the internet
through a proxy connection. After some time, there appears an error
message in the browser which I can't interprete:

HTTP/1.0 200 OK Content-Type: text/html;charset=ISO-8859-1 Pragma: 
no-cache Expires: Thu, 01 Jan 1970 00:00:00 GMT Servlet-Engine: Tomcat
Web Server/3.2.1 (JSP 1.1; Servlet 2.2; Java 1.2.2; Windows NT 4.0 x86;
java.vendor=Sun  Microsystems Inc.) X-Cache: MISS from proxy2.xxx.xxx
X-Cache-Lookup: MISS from proxy2.xxx.xxx:80 Age: 0 X-Cache: MISS from 
squid.xxx.xxx Proxy-Connection: close

I use Session-cookies and send bravely an:

response.setHeader("Pragma", "no-cache");
response.setDateHeader("Expires", 0L);

Some Ideas which I have are:
1) Set "Cache-Control" "no-store"- I didn't use this because of
compatibility issues with the IE4.01 Browser, but the support of
IE4.01 is not a must.
2) There is a button in IE >5.0 "Use HTTP/1.1 over proxy connections"
- is this the crucial setting?

Can anybody help me with this problem?

Thanks in advance,
Michael