YOur problem is in the warn_viewtype_top and warn_viewtype_row, not in add_warn.
Here is what they should look like:
warn_viewtype_top
<table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%" align="center">
<thead>
<tr>
<td class="tcat" colspan="8">
<a style="float:$stylevar[right]" href="#top" onclick="return toggle_collapse('warn_listtype')"><img id="collapseimg_warn_listtype" src="$stylevar[imgdir_button]/collapse_tcat$vbcollapse[collapseimg_warn_list].gif" alt="" border="0" /></a>
Warning Types
</td>
</tr>
</thead>
<tbody id="collapseobj_warn_listtype" style="$vbcollapse[collapseobj_warn_list]">
<tr>
<td class="thead">Warning Name</td>
<td class="thead">Warning Description</td>
<td class="thead">Warning Points</td>
<td class="thead">Warning Maturity</td>
<td class="thead">Permanent Ban</td>
<td class="thead">Post-related</td>
<td class="thead">Alertable</td>
<td class="thead">Alert Comment</td>
</tr>
warn_viewtype_row
<tr>
<td class="alt1"><b>{$warn['warn_name']}</b></td>
<td class="alt1">{$warn['warn_desc']}</td>
<td class="alt1">{$warn['warn_points']}</td>
<td class="alt1">{$warn['warn_maturity']}</td>
<td class="alt1">{$warn['warn_permban']}</td>
<td class="alt1">{$warn['warn_type']}</td>
<td class="alt1">{$warn['warn_alert']}</td>
<td class="alt1">$warntypecomment</td>
</tr>
Rgds