cannot upload, add folders or comments, "loss of session data"

joomla 1.0.13
gallery2
cb
advanced seo

"Your change cannot be completed due to a loss of session data. Please try again. If it still doesn't work, try logging out and logging back in."

I get this error when i add subalbum or add comment or add a photo to album. latest gallery2 + joomla. this error is here for almost a year. first if i took off the url rewrite and permalinks, it doesnt show the error in internet explorer, but does on firefox!! of course i cleaned cache, sessions, everything.. then i found a difference - internet explorer wasn`t showing UTF-8 characters (just ignored the meta charset tag). so i added header(charset:utf8) in index.php of my joomla install and now internet explorer shows the pages correctly with utf8characters, but gallery2 throws "loss of session data"
Now I understand why my other site doesn`t throw this error - i use only english on that site! (but then again url_rewrite doesnt work there, but not that big problem as this)

I attached two error files - one is direct copy and past from the webpage while trying to add an album, second is smarty popup debug data.
and yes, my server uses safe mode on, but i CAN upload directly from standalone G2. not from embedded
Hope this helps!
Valters

seems everything works through embed except one thing - if i delete a user album, the user cannot login anymore through embedded view. blank page. when logged in via g2 and clicked on "your album" (creates a useralbum), then everythings fine