"The underlying connection was closed" error in the RescueTime application

I get this error when attempting to Verify, or Send Update Now. I'm running on windows XP, as an admin.

Did a bit of investigation, it looks like a proxy server issue. I ran wireshark while clicking the verify button, and got the following trace of the http request:

POST /api/handshake HTTP/1.1
Host: api.rescuetime.com
Content-Length: 44
Expect: 100-continue
Connection: Close

email=MY USERNAME&password=MY PASSWORD

HTTP/1.0 100 Continue
Date: Fri, 16 Nov 2007 14:46:47 GMT
X-Cache: MISS from furnace
X-Cache-Lookup: MISS from furnace:3128
Via: 1.1 ctb-cache7 (NetCache NetApp/6.1.1D3), 1.1 wrbs-ip-ccache-1 (NetCache NetApp/6.1.1D2), 1.0 furnace:3128 (squid/2.6.STABLE1)
Connection: close

furnace is our (transparent) office proxy server, and it looks like the rescuetime server is not downgrading the request to an http 1.0 request...

Don't know if this is fixable :), but would be nice, as i cannot use RescueTime at work...