I have a problem when I try to send a Post Method

Sixten Otto

If you are running this applet from within Internet Explorer 5, you may be running afoul of a known bug with using URLConnection to issue a POST request from within an applet.

You might want to try running your applet from Netscape, iCab, or Apple's Applet Runner to determine whether this bug in IE5 is your problem.

Here's some more information about how you might be able to work around the bug: Apple's Q&A Java 26. It has been discussed many times on the Apple java-dev mailing list, but the archives of that list are not currently searchable, I'm afraid.