Squid causing websocket issues

I am running squid 2.x. When trying to use websockets in my web application I get the following in my squid logs

13/Jun/2012:10:05:08 +1000    558 192.168.19.76 TCP_MISS/100 199 POST http://api.pusherapp.com/apps/21932/channels/2830b5dd-e75b-4788-ae4a-6da903460d22/events? - DIRECT/107.22.252.43 -

TCP_MISS/100 indicates that the service is returning the wrong thing from what I can see.

What can I do to fix this?

TCP_MISS/100 it's means that the request not found on the squid cache and the service returned http code 100 which, according to the RFC, means;

10.1.1 100 Continue

The client SHOULD continue with its request. This interim response is used to inform the client that the initial part of the request has been received and has not yet been rejected by the server. The client SHOULD continue by sending the remainder of the request or, if the request has already been completed, ignore this response. The server MUST send a final response after the request has been completed. See section 8.2.3 for detailed discussion of the use and handling of this status code.

are you sure, that you sent a correct request to the service ? also check this link http://benramsey.com/blog/2008/04/http-status-100-continue/