It's because the site is checking you're a valid browser, you'll have to recompile the source and set the Agent to something the site will recognize, this seems to work:
procedure TRtcFileClient.btnPostClick(Sender: TObject);
begin
with DataRequest do
begin
with Request do
begin
Agent := 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9.0.7) Gecko/2009021910 Firefox/3.0.7';
Method:=AnsiString(eReqMethod.Text);
FileName:='/'+AnsiString(eReqFileName.Text);
Query.Text:=AnsiString(eReqQuery.Text);
Host:=AnsiString(eReqHost.Text);
if xSaveToFile.Checked then
Info.asText['fname']:=eFileName.Text;
end;
Post;
end;
end;
Steve..