[Quarterbore]

There is at least one (perhaps 2) security token errors in the product file.

In Template: pmsearch

FIND:

PHP Code:

<form action="private.php?pmsearch=1" method="post"> 


AFTER ADD:

PHP Code:

<input type="hidden" name="s" value="$session[sessionhash]" />
<input type="hidden" name="securitytoken" value="$bbuserinfo[securitytoken]" /> 


Next (in same template) find:

PHP Code:

<form action="private.php?do=managepm&amp;folderid=$folderid" method="post">
<input type="hidden" name="s" value="$session[sessionhash]" /> 


AFTER ADD:

PHP Code:

<input type="hidden" name="securitytoken" value="$bbuserinfo[securitytoken]" /> 


Then it works in 3.7.x