C'est bien ça, dans ton thème tu as ceci :
Affichage des blocs de la colonne gauche
<table cellspacing="0">
<tr>
<td id="leftcolumn">
<!-- Start left blocks loop -->
<{foreach item=block from=$xoops_lblocks}>
<{include file="orange_peco/theme_blockleft.html"}>
<{/foreach}>
<!-- End left blocks loop -->
</td>
Affichage des blocs de la colonne centrale
-> Blocs centre centré
<td id="centercolumn">
<!-- Display center blocks if any -->
<{if $xoops_showcblock == 1}>
<table cellspacing="0">
<tr>
<td id="centerCcolumn" colspan="2">
<!-- Start center-center blocks loop -->
<{foreach item=block from=$xoops_ccblocks}>
<{include file="orange_peco/theme_blockcenter_c.html"}>
<{/foreach}>
<!-- End center-center blocks loop -->
</td>
</tr>
-> Blocs centre - gauche
<tr>
<td id="centerLcolumn">
<!-- Start center-left blocks loop -->
<{foreach item=block from=$xoops_clblocks}>
<{include file="orange_peco/theme_blockcenter_l.html"}>
<{/foreach}>
<!-- End center-left blocks loop -->
</td>
-> Blocs centré droit
<td id="centerRcolumn">
<!-- Start center-right blocks loop -->
<{foreach item=block from=$xoops_crblocks}>
<{include file="orange_peco/theme_blockcenter_r.html"}>
<{/foreach}>
<!-- End center-right blocks loop -->
</td>
</tr>
</table>
<{/if}>
<!-- End display center blocks -->
Affichage du contenu du module
<div id="content"><{$xoops_contents}></div>
</td>
<{if $xoops_showrblock == 1}>
Affichage de la colonne de droite.
<td id="rightcolumn">
<!-- Start right blocks loop -->
<{foreach item=block from=$xoops_rblocks}>
<{include file="orange_peco/theme_blockright.html"}>
<{/foreach}>
<!-- End right blocks loop -->
</td>
<{/if}>
</tr>
</table>
Bref ce theme html ne t'affichera jamais tes blocs centre bas, il manque le code !
