You do *not* post the actual source code of the sheet--it will not post correctly.
After you post a message, the board will automatically re-direct you to the thread you just posted to after a couple of seconds. I've seen your posts in the test forum (but deleted them without looking at the posted code), and saw that the "Quick Reply" window was displaying in the wrong place--I'm assuming this is what you mean by "the board redirects me to post a reply to the message I was posting."
Basically, the code you posted is causing the page to display incorrectly (I have since deleted those posts from the test forum).
I don't have XP on the computer I'm on at the moment so I can't really check this out--but going from memory, when the popups are blocked and the message appears at the top of the IE window I believe there is an option to "*always* allow blocked content from...," is there not? If yes, go ahead and select that so you should not have to do that every time.
Also, have you tried refreshing the page or running the addin again after getting past the IE popup?
At any rate, the code you should use is generated by the HTML Maker add-in, but NOT the source code of the page--you can click the "View Source" button that displays on the page and it should then display a text box with the generated code. Just copy it from there and paste it into the sheet.