Help, FATAL ERROR

While on backend and creating a SEF URL, when I went to save: the screen gave the following:

Fatal error: Cannot instantiate non-existent class: jsite in /home/@@@/public_html/components/com_sef/sef.php on line 0

I have recently upgrade joomla to 1.5.10, other than that, nothing (I know of) has changed related to SEFA.

Please advise.

Which version of SEF Advance?

Joomla 1.5.10

SEF Advance: 2.0.5

Please send a mail with the access info.

Emir, I sent you the details for the site, did you receive them?  I need to get this problem addressed please.

It appears I was misusing the SEF component.  I was attempting to use it to create Meta Descriptions on URL's it had already generated for paginated pages  there by creating an SEF of and SEF.  I was simply trying to add the meta tags to items my data was showed had dupes.