/session unwitable

I have major problems wit SefAdvance.  Some links of content items from my hompeage are working some not.
See previous post.
Could anyone help me by looking in?? I have purchased (think) advance sef a year ago for www.medischondernemen.nl

In diagnostics i get:

Session Directory /var/lib/php/session/ Unwriteable

but in xplorer the settings are writable...

It can be because of misconfiguration. Please see:
www.sakic.net/support/faq/sef_advance/#18

The support of IJoomla (excellent BTW) helped me out a while ago.
Don't understand fully, but this is what they did:

In components/com_sef/joomsef.php file is a function called "getMenuTitle"
where Artio sef make a select in database to find section title from menu.
"SELECT name$jfTranslate FROM #__menu WHERE link = 'index.php?option=$option'"
This select don’t verify after "published=1" and if exist in table #__menu, old registration with the same name, code do some trouble even they are unpublished or deleted.
In your case (www.medischondernemen.n) there were 2 more registrations in table which were deleted/unpublished but code crashed.
I modified field “link” from "index.php?option=com_news_portal" in "index.php?option=com_news_portal2" and works.