so geht´s.
scheinbar ist ein position:relative; auf td nicht defniert.
http://www.w3.org/TR/CSS21/visuren.html#positioning-scheme:
"The effect of 'position:relative' on table-row-group, table-header-group, table-footer-group, table-row, table-column-group, table-column, table-cell, and table-caption elements is undefined."
<head>
<style>
td.c1 p {background:green; position:relative; margin:0; padding:0}
td a.l {color:red; position:absolute; right:1px; bottom:1px;}
</style>
</head>
<table border="1">
<tr>
<td width=300px>spalte1</td>
<td width=300px class='c1'><p>spalte2<br/>zeile zwo<a href='#' class='l'>Link</a></p></td>
<td width=300px>spalte3</td>
</tr>
</table>