phpMyAdmin session error

[Allfreeware]

Hi all.
I'm using xampp.
I've used it a lot but now,i don't know why,it give me this error when i try to access at "phpmyadmin" from the xampp main page:
this is the error
A translation of it could be:
"Cannot start the session without errors,check errors in php log and/or in you're web server and configure you're php installation correctly."

How can i solve it?

Thanks.