[dev] session id contains illegal characters ... ?

[Marc G. Fournier]

Just upgrading the demo site from CVS, and am seeing the following error
when trying to login ... /tmp is fine, with proper permissions ...
something else I should be looking at?

Warning: Unknown(): The session id contains illegal characters, valid characters are only a-z, A-Z and 0-9 in Unknown on line 0

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