在Blackberry Webworks上发送带头文件的AJAX请求时出现问题

I am developing a Blackberry webworks application and I am having trouble with an AJAX request that I am making to a server. I am learning HTML/Javascript/AJAX on the fly, so excuse any beginner mistakes. Basically, formatted HTTP requests are made to the server, which returns JSON objects that I use in the application. I am using AJAX to make the requests without any kind of framework. Most requests do not have to be authenticated, and those are returning just fine. However, to access a directory part of the server, a username and password are encoded and sent as a header with the XMLHTTPRequest. when I try and add the header, the request is sent, but I never get anything back. The readyState property is set to 1, but never goes beyond that. I know the server works fine, because I did the same thing for iPhone, and it worked.I am developing a Blackberry webworks applicati