Your posts disappear because you are using a '<' sign to mark a quote from someone. To stop HTML being placed into posts the forum now strips all tags (apart from bold, italic) out of the post. The system sees your '<' as the start of a bit of HTML and so removes everything between it and the closing '>'. That closing bracket isn't there so the whole message goes.

If you want to use '<' then you'll have to type &lt;. It may be easier if you could choose a different marker :-)

Thanks

TMA Ed