[horde] session.save_path problem

[Rodrigo Gressler]

Hello all,

We are installing horde with IMP on a debian woody machine. On php.ini 
we have set session.save_path to "/tmp". But this value remains on "0".

Here is the warning messages from the horde page:
"..
Warning: open(0/sess_b5e5809eb91e8144c907114b33fb4151, O_RDWR) failed: 
No such file or directory (2) in Unknown on line 0

Warning: Failed to write session data (files). Please verify that the 
current setting of session.save_path is correct (0) in Unknown on line 0
.."

I already search on Google but I didn't find a solution for it.

Can anyone help me?

TIA,

Rodrigo Gressler