have you still got new-lines and tabs etc in the table cells code?
I think it is IE that sometimes decides some blocks need more space when it has these in, even if there's nothing in there to render on screen.
(so try putting the <td>...</td> all on ONE SINGLE line, and only have spaces inside the < > tags...
Code:
<td><form name="cell1"><input type="submit" image="cell1.gif"></form></td>
check that margin is 0px for <img>s and <input>s
Show us the offending page!