Unable to set up default locale

[RandyFisher]

I updated Plesk from version 8.4 to version 10.1.1 and now I got following error message:

ERROR: PleskFatalException
Unable to create Session object: Unable to set up default locale: default locale does not exist or undefined.

0: common_func.php3:95
psaerror(string 'Unable to create Session object: Unable to set up default locale: default locale does not exist or undefined.')
1: auth.php3:186

Is there any way to solve the problem?
I already tried using server_prev and /admin, but the I got:

Can't initialize session: Unable to set up default locale: default locale does not exist or undefined.

 

[RandyFisher]

Could anyone help me please?

 

[RandyFisher]

*push* Still need some help.

 

[IgorG]

http://forum.parallels.com/showthread.php?t=101493