why the upload failed frequently?

[redrum pam]

I have use ASIHTTPRequest to upload some video on the iPad to a http
server, It may success, but failed frequently.

I changed to ASIFormDataRequest, and the same happened, some times I
got a error says "Libinfo call to mDNSResponder on main thread",
others time only failed. How can I found why this happened?

the codes looks like

ASIHTTPRequest *request;

request = [ASIHTTPRequest requestWithURL:[NSURL
URLWithString:urlString]];

[request appendPostDataFromFile:uploadRequest.fileFullPath];
[request addRequestHeader:@"Content-Type" value:@"application/
octet-stream"];
[request setShouldStreamPostDataFromDisk:YES];

[request setShouldContinueWhenAppEntersBackground:YES];

if (uploadRequest.progressDelegate) {
[request
setUploadProgressDelegate:uploadRequest.progressDelegate];
}
else {
[request
setUploadProgressDelegate:uploadRequest.progressView];
}
[request setUserInfo:[NSDictionary
dictionaryWithObject:uploadRequest.productGuid
forKey:@"productGuid"]];
[networkQueue addOperation:request];
if ([networkQueue isSuspended]) {
[networkQueue go];
}

[G S]

We're experiencing this too.  Does anybody know what this message means, and whether it is associated with upload failures?

In the console we occasionally see (for our app)

Warning: Libinfo call to mDNSResponder on main thread

Thanks!