The problem is, that every newline character is converted into a break tag when you post. So, your code is going to end up looking something like:
<table>
<br />
<tr>
<br />
<td>
<br />
and so on.
All those break tags in between the table,tr,td tags are rendered outside of the table giving you a big gab at the top. So, when posting table stuff, you need to do it on one line:
<table><tr><td>blah blah blah</td><td>blah blah blah</td></tr></table>
