[squid-users] Read error when transmitting forms

Hello,

I'm experiencing a strange problem with Squid 2.3.STABLE4 on Debian
GNU/Linux 2.2. Until recently, this machine was connected to the
Internet trough an ISDN-connection. Nowadays, it's connected to an
Intranet(called Kennisnet, a nationwide Dutch educational network) with a
ethernet card which is connected to a Cisco router. Kennisnet provides
Internet access through a nationwide proxy. I've configured this proxy as a
parent for my instance of squid. (proper cache_peer line, and never_direct
allow all,always_direct deny all). The clients on my local networks can now
access static content on the internet through squid without errors and on
full speed. The problems start, however, when the local clients want to
access dynamic content(forms, URLS with a ?-symbol). Squid almost
immediately reports a "read error" to the user's browser(Connection reset
by peer while retrieving URL <no URL>). In order to isolate the problem,
I've redirected my local proxy's port to the upstream's proxy port(with
redir, a linux port forwarder) and then my clients can send forms and
access dynamic content flawlessly. My conclusion: something goes wrong with
squid.

Some snippets from the log file with debug level 9:
<I'm trying to send a form with the URL http://computer.2ehands.nl/mz.html
from local client
192.168.17.11 through upstream proxy proxy.kennnisnet.nl>

---
Start of the request:
2001/03/16 14:54:00| comm_poll: FD 14 ready for reading
2001/03/16 14:54:00| clientReadRequest: FD 14: reading request...
2001/03/16 14:54:00| commSetSelect: FD 14 type 1
2001/03/16 14:54:00| parseHttpRequest: Method is 'POST'
2001/03/16 14:54:00| parseHttpRequest: URI is 
'http://computer.2ehands.nl/mz.html'
2001/03/16 14:54:00| parseHttpRequest: req_hdr = {Referer: 
http://computer.2ehands.nl/mz.html?dbase=hele_systemen
Host: computer.2ehands.nl
User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; m18) Gecko/20010131 
Netscape6/6.01
Accept: */*
Accept-Language: en
Accept-Encoding: gzip,deflate,compress,identity
Keep-Alive: 300
Connection: keep-alive
Content-type: application/x-www-form-urlencoded
Content-Length: 182
}
2001/03/16 14:54:00| parseHttpRequest: end = {}
2001/03/16 14:54:00| parseHttpRequest: prefix_sz = 428, req_line_sz = 50
2001/03/16 14:54:00| cbdataAdd: 0x842a108
2001/03/16 14:54:00| parseHttpRequest: Request Header is
Referer: http://computer.2ehands.nl/mz.html?dbase=hele_systemen
Host: computer.2ehands.nl
User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; m18) Gecko/20010131 
Netscape6/6.01
Accept: */*
Accept-Language: en
Accept-Encoding: gzip,deflate,compress,identity
Keep-Alive: 300
Connection: keep-alive
Content-type: application/x-www-form-urlencoded
Content-Length: 182
2001/03/16 14:54:00| parseHttpRequest: Complete request received
----
Right peer selected:
2001/03/16 14:54:00| peerSelectFoo: 'POST computer.2ehands.nl'
2001/03/16 14:54:00| peerSelectFoo: direct = DIRECT_NO
2001/03/16 14:54:00| peerSelectIcpPing: http://computer.2ehands.nl/mz.html
2001/03/16 14:54:00| neighborsCount: 0
2001/03/16 14:54:00| peerSelectIcpPing: counted 0 neighbors
2001/03/16 14:54:00| peerGetSomeParent: POST computer.2ehands.nl
2001/03/16 14:54:00| getDefaultParent: returning proxy.kennisnet.nl
2001/03/16 14:54:00| peerSelect: DEFAULT_PARENT/proxy.kennisnet.nl
2001/03/16 14:54:00| peerAddFwdServer: adding proxy.kennisnet.nl DEFAULT_PARENT
----
And the moment it goes wrong, i think:
2001/03/16 14:54:01| comm_poll: FD 21 ready for reading
2001/03/16 14:54:01| httpReadReply: FD 21: len 0.
2001/03/16 14:54:01| fwdComplete: http://computer.2ehands.nl/mz.html
         status 200
2001/03/16 14:54:01| fwdReforward: http://computer.2ehands.nl/mz.html?
2001/03/16 14:54:01| fwdReforward: No, ENTRY_FWD_HDR_WAIT isn't set
2001/03/16 14:54:01| fwdComplete: not re-forwarding status 200
--------------
I may be missing an important part of the log, but it's far too big to 
completely post it to this list. Does anyone have an idea what is causing 
this problem and how to solve it??