I have found a readmorelink.php file that had the following code...
// Get the article URL from $article->readmorelink not is a good idea
// Jooma 1.5 don't generate value for readmore_link for some situations
// like the frontpage
// Thanks to Goran Stetic for discover this bug.
//$route=$article->readmore_link;
$route=JRoute::_(ContentHelperRoute::getArticleRoute($article->slug, $article->catslug, $article->sectionid));
$link="";
$article->text=str_ireplace('{readmorelink}', $link, $article->text);
$article->text=str_ireplace('{/readmorelink}', '', $article->text);
}
else {
$article->text=preg_replace('#{readmorelink}(.*?){/readmorelink}#s', '', $article->text);
$article->text=str_ireplace('{readmorelink}', '', $article->text);
$article->text=str_ireplace('{/readmorelink}', '', $article->text);
}
But I dont know enough about code to know if this is the problem or how to fix it.
The readmore link works on everything other than the frontpage.