Another user that can't attach to the project

My old machine was running 4.something quite happily. On a new machine I did a clean install of the new version 5.2.2. I've attached okay to seti@home, but it refuses to attach to Einstein. I selected "existing account", and entered the same details I just used to log in here, but it just goes away for a bit then tells me it can't connect. Checking the proxy server logs (and no, I can't avoid going through the proxy) I see the following:

+++GET 216+++
GET http://einstein.phys.uwm.edu/get_project_config.php HTTP/1.1
User-Agent: BOINC client (windows_intelx86 5.02)
Host: einstein.phys.uwm.edu
Pragma: no-cache
Accept: */*
Content-Type: application/x-www-form-urlencoded
Connection: keep-alive
Browser reload detected...
+++RESP 216+++
HTTP/1.1 200 OK
Connection: close
Date: Fri, 28 Oct 2005 10:22:12 GMT
Server: Apache/2.0.53 (Fedora)
X-Powered-By: PHP/4.3.11
Content-Length: 157
Content-Type: text/xml
Age: 0
+++CLOSE 216+++

+++GET 217+++
GET http://einstein.phys.uwm.edu//lookup_account.php?email_addr=&passwd_hash= HTTP/1.1
User-Agent: BOINC client (windows_intelx86 5.02)
Host: einstein.phys.uwm.edu
Pragma: no-cache
Accept: */*
Content-Type: application/x-www-form-urlencoded
Connection: keep-alive
Browser reload detected...
+++RESP 217+++
HTTP/1.1 200 OK
Connection: close
Date: Fri, 28 Oct 2005 10:22:29 GMT
Server: Apache/2.0.53 (Fedora)
X-Powered-By: PHP/4.3.11
Content-Length: 139
Content-Type: text/xml
+++CLOSE 217+++

+++GET 218+++
GET http://einstein.phys.uwm.edu/ HTTP/1.1
User-Agent: BOINC client (windows_intelx86 5.02)
Host: einstein.phys.uwm.edu
Pragma: no-cache
Accept: */*
Content-Type: application/x-www-form-urlencoded
Connection: keep-alive
Browser reload detected...
+++RESP 218+++
HTTP/1.1 200 OK
Connection: close
Date: Fri, 28 Oct 2005 10:22:31 GMT
Server: Apache/2.0.53 (Fedora)
X-Powered-By: PHP/4.3.11
Content-Length: 7390
Content-Type: text/html
Age: 0
+++CLOSE 218+++

+++GET 219+++
POST http://einstein.phys.uwm.edu/EinsteinAtHome_cgi/cgi HTTP/1.1
User-Agent: BOINC client (windows_intelx86 5.02)
Host: einstein.phys.uwm.edu
Pragma: no-cache
Accept: */*
Content-Type: application/x-www-form-urlencoded
Content-Length: 4591
Expect: 100-continue
Connection: keep-alive
Browser reload detected...
Posting 4591 bytes...
Continue ignored...
+++RESP 219+++
HTTP/1.1 503 Service Unavailable
Connection: close
Cache-Control: no-cache
Pragma: no-cache
Content-Type: text/html
Content-Length: 682
+++CLOSE 219+++

I'm assuming the servers haven't been down the last two days since there's been nothing on the web site about it. I'm obviously able to reach the Einstein server okay, as the first couple of requests show. My guess is that maybe something about the "100-continue" on the last request is causing the problem, but if that's so then why is Seti@home okay?

Andrew.