Fejl i preg_replace

<?php
function dobbcode($string) {
$string = preg_replace("#[img]((ht|f)tp://)([^ <"]*?)[/img]#sie", "'<img src=\1' . str_replace(' ', '%20', '\3') . '>'", $string);
$string = preg_replace("#[url]((ht|f)tp://)([^ <"]*?)[/url]#sie", "'<a href="\1' . str_replace(' ', '%20', '\3') . '" target=blank>\1\3</a>'", $string);
$string = preg_replace("/(.+?)/s", "<a href=$1 target=blank>$2</a>", $string);
$string = preg_replace("/(.+?)/s", "<b>$1</b>", $string);
$string = preg_replace("/(.+?)/s", "<i>$1</i>", $string);
$string = preg_replace("/(.+?)/s", "<u>$1</u>", $string);
$string = preg_replace("/[code](.+?)[/code]/g", "<table width="100%" border="1" bordercolor="black" bgcolor="#f7f7f7" style="BORDER-COLLAPSE: collapse"><tr><td align="left"><code><br>$1<br></code></td></tr></table>", $string);
$string = preg_replace("/[quote](.+?)[/quote]/g", "<table width="100%"><tr><th align="left"><font face="tahoma">Gengivelse:</font></th></tr><tr><td align="left">$1</td></tr></table>", $string);
$string = preg_replace("/[quote=(.+?)](.+?)[/quote]/g", "<table width="100%"><tr><th align=left>$1 :</th></tr><tr><td align="left">$2</td></tr></table>", $string);
$string = preg_replace("/[color=(.+?)](.+?)[/color]/s", "<font color="$1">$2</font>", $string);
$string = preg_replace("#[IMG]((ht|f)tp://)([^ <"]*?)[/IMG]#sie", "'<img src=\1' . str_replace(' ', '%20', '\3') . '>'", $string);
$string = preg_replace("#[URL]((ht|f)tp://)([^ <"]*?)[/URL]#sie", "'<a href="\1' . str_replace(' ', '%20', '\3') . '" target=blank>\1\3</a>'", $string);
$string = preg_replace("/[URL=(.+?)](.+?)[/URL]/s", "<a href=$1 target=blank>$2</a>", $string);
$string = preg_replace("/[B](.+?)[/B]/s", "<b>$1</b>", $string);
$string = preg_replace("/[I](.+?)[/I]/s", "<i>$1</i>", $string);
$string = preg_replace("/[U](.+?)[/U]/s", "<u>$1</u>", $string);
$string = preg_replace("/[CODE](.+?)[/CODE]/g", "<table width="100%" border="1" bordercolor="black" bgcolor="#f7f7f7" style="BORDER-COLLAPSE: collapse"><tr><td align="left"><code><br>$1<br></code></td></tr></table>", $string);
$string = preg_replace("/[QUOTE](.+?)[/QUOTE]/g", "<table width="100%"><tr><th align="left"><font face="tahoma">Gengivelse:</font></th></tr><tr><td align="left">$1</td></tr></table>", $string);
$string = preg_replace("/[QOUTE=(.+?)](.+?)[/QOUTE]/g", "<table width="100%"><tr><th align=left>$1:</th></tr><tr><td align="left">$2</td></tr></table>", $string);
$string = preg_replace("/[COLOR=(.+?)](.+?)[/COLOR]/s", "<font color="$1">$2</font>", $string);
return $string;
}
?>

Hvorfor bliver teksten blank, når jeg kører en post igennem den?