That error seems to be in the function setupThemeContext from the line number.
The line in my last reply is next to the other one. I actually missed a third line.
Here's what to replace from the original RC2 Subs.php:
<edit file>
$sourcedir/Subs.php
</edit file>
<search for>
'~\[quote(?: author)?="(.{1,80}?)"\](?:<br />)?~i' => isset($disabled['quote']) ? '<div>' : '<div class="quoteheader">' . $txt['smf239'] . ': $1</div><div class="quote">',
'~\[quote author=(.{1,80}?) link=(?:board=\d+;)?((?:topic|threadid)=[\dmsg#\./]{1,40}(?:;start=[\dmsg#\./]{1,40})?) date=(\d+)\](?:<br />)?~ei' => isset($disabled['quote']) ? '\'<div>\'' : '\'<div class="quoteheader"><a href="' . $scripturl . '?$2">' . $txt['smf239'] . ': $1 ' . $txt[176] . ' \' . timeformat(\'$3\') . \'</a></div><div class="quote">\'',
'~\[quote author=(.{1,80}?)\](?:<br />)?~i' => isset($disabled['quote']) ? '<div>' : '<div class="quoteheader">' . $txt['smf239'] . ': $1</div><div class="quote">',
</search for>
<replace>
'~\[quote(?: author)?="(.{1,80}?)"\](?:<br />)?~i' => isset($disabled['quote']) ? '<div>' : '<div class="quoteheader">$1 ' . $txt['quote_said'] . ':</div><div class="quote">',
'~\[quote author=(.{1,80}?) link=(?:board=\d+;)?((?:topic|threadid)=[\dmsg#\./]{1,40}(?:;start=[\dmsg#\./]{1,40})?) date=(\d+)\](?:<br />)?~i' => isset($disabled['quote']) ? '<div>' : '<div class="quoteheader"><a href="' . $scripturl . '?$2">$1 ' . $txt['quote_said'] . ':</a></div><div class="quote">',
'~\[quote author=(.{1,80}?)\](?:<br />)?~i' => isset($disabled['quote']) ? '<div>' : '<div class="quoteheader">$1 ' . $txt['quote_said'] . ':</div><div class="quote">',
</replace>
[/quote][/quote][/quote][/quote]