[Lynne]

The problem is, you already have a static width of 50 (although you really should say "50px", not just "50"):
<td class="alt2" width="50" style="border: $stylevar[cellspacing]px solid $stylevar[tborder_bgcolor]; border-top: 0px; border-bottom: 0px">

However, you obviously have avatars that are much wider which will push the table column out. So, you can either change that width to something a bit wider than what the allowable avatar width is, or you can resize the avatars in the postbit.

edit: Disregard the comment about using 50px in your table statement.