Description:
------------
PHP seems to have some problems with frames, in my case iframes. I noticed this error when I tried to load  one template in two separate iframes. If they are loaded simultanously there comes to a problem with session variables getting lost. And also getting Permission denied(13) in session_start(). As it seems PHP doesn't check if the session file is already in use.

To reproduce the actual result, you have to click on a link 'odpri' atleast 5-15 times

Reproduce code:
---------------
main.php
<? session_start(); ?>

<? $_SESSION['name'] = 'iztok'; ?>
<a href="#" onClick="bla.location.href = 'left.php';bla2.location.href = 'right.php';">odpri</a><br><br>
<iframe name="bla" width="100%" height="100"></iframe>
<iframe name="bla2" width="100%" height="100"></iframe>

left.php
<? session_start(); ?>
<? print $_SESSION['name']; ?>

right.php
<? session_start(); ?>
<? print $_SESSION['name']; ?>


Expected result:
----------------
iztok

Actual result:
--------------
Warning: session_start() [function.session-start]: open(c:\php\sessiondata\sess_793ef570090b599c6d973dfc64696a46, O_RDWR) failed: Permission denied (13) in C:\Documents and Settings\Iztok\My Documents\My Website\left.php on line 1