Can you post your entire request?
Sure, here's a tcpflow dump of a failing request:
CODE
010.112.009.138.37773-098.136.145.152.00080: POST /ws/mail/v1.1/jsonrpc HTTP/1.1
Accept: */*
Connection: close
Content-Type: application/json
Authorization: OAuth oauth_consumer_key="dj0yJmk9NGZEM1VhaGRaTDVrJmQ9WVdrOVVVczVSVmxQTkdzbWNHbzlNekkwTXpneE1EWXkmcz1j
b25zdW1lcnNlY3JldCZ4PWY4", oauth_nonce="qFHMZx7yO5vST3yfgoiajabk6nlq2asHbiR8sSjvQ", oauth_signature="Nks5Fc4A%2BBolaTEI9%2FsA4qr2JJE%3D", oauth_signature_method="HMAC-SHA1", oauth_timestamp="1288817356", oauth_token="A%3DRauc9zfMj1oe32kNADvyYIj4gccu6ZyV.sfqFnQfhipNqRc.HGU3vHpMbeU_u.nY9Zl.gnCadGrPZd
yEXcMisQpb99Z3MkVsfqHQP9uPvDXclKHHCLDZkNU50U6Zgt9crw5FwMCetYgWWd5C6WvBmVRD7uy2SMU
_CV1GKWtXcxkvQ1NeBqZKE84UQuU6gxfaK4TEVf0ANngsTXnYQJz8fYxNvRaBQdkcVqqjLnWhy1yfgI_2
UkMyVqIx.bxCTPo.oAbGAnPn_.ltaYIjzMX0l_3lSqe.aRTMpz803EpcAi4hHL_PxuogCp5FV_.0U8px4
cZOYtYlM_RnKhPYKA5V3XqqLm62NEE9nJgGr_N.Yv.DJgtTh0uc765Lthoob8bIBm07ZvCViYdoIwp1LY
c1jW2tpXzL5RAHeaAVN1Kjwbh9TbKbYus9LEG_23tmE7jxK.6p3s1pAKCkZCPvqzfsoHPLY1sqktT3dNR
gg58wvq3LrxMWhUOxmiigZu6xjJJWmMpuJzYzk7wxRT9SykTMi56.Wpd3ERhQlS2SZRorXnW4GBn2cR64
oDMrfh2QxjQbMV_7NE9RwoehcjtUwlYX55sUkGjbXEEqzNJ9RhJbd3jVBPTtdSFbdASakfCtBAZm.TuM0
NYl26d_L8kjEI1_sdNBpZhAkI_ppilHHqytPKtOqAhxDo_baQBbnvMBNyyHjbEFmlcjyOLgzO0KqEuC8O
XJ9X_NxU0F45K_vZYq0IoP6DbdSka_1HH45otX8si2ObPxqSkPHdfO", oauth_version="1.0"
Content-Length: 64
Host: mail.yahooapis.com
010.112.009.138.37773-098.136.145.152.00080: {"params":[{"resetMessageUnseen":false}],"method":"ListFolders"}
098.136.145.152.00080-010.112.009.138.37773: HTTP/1.1 404 Not Found on Accelerator
Date: Wed, 03 Nov 2010 20:49:16 GMT
Connection: close
Via: HTTP/1.1 r04.ycpi.ac4.yahoo.net (YahooTrafficServer/1.19.5 [c s f ])
Server: YTS/1.19.5
Cache-Control: no-store
Content-Type: text/html
Content-Language: en
Content-Length: 240
<HEAD><TITLE>Not Found on Accelerator</TITLE></HEAD>
<BODY BGCOLOR="white" FGCOLOR="black">
<FONT FACE="Helvetica,Arial"><B>
Your requested URL was not found.</B></FONT>
<!-- default "Not Found on Accelerator" response (404) -->
</BODY>