btw, i started indenting my coding laserlight (i have this program that does it for me 😃 , though on here if i copy and paste it doesn't indent and i don't have the time to do it myself.)
anyways, the parse error is somewhere in the middle line, it needs a '," or';"
echo "<tr>
<td align="center" class=\"cell2\" width="15%">
<b><a href=\"whois.php?user=".$u["userid"]."&board=".$board."&topic=".$topic."\">
".$u["username"]."</a></b></td>
<td class=\"cell2\" valign="top">
<b>Posted:</b> ".str_replace(" "," ",gmdate
("n/j/Y h:i:s A",($m["messsec"]+$time_offset)))." |
<a href=\"detail.php?board=".$board."&topic=".$topic."&message=".$m["messageid"]."\">Message Detail</a>";