session not writing

we are using sessions as a authentication model (linux/apache/php4) however it is not "always" writing the session file to /tmp & the session.save_path is correct in the php.ini (ie its writing is highly inconsistent...sometimes it will...sometimes it won't) It will create the file but the session data is not written and the file is 0 bytes. the error log says "<b>Warning</b>: Failed to write session data. Please check that the current setting of session.save_path is correct (/tmp) in <b>Unknown</b> on line <b>0</b><br>"...duh any help would sooo greatly appreciated...its driving me nuts many thanks in advance!!! -- Christian Haines Newsbreaker Webwork 17 Laurel Road, Stirling South Australia 5152 Ph 61 8 8370 9088 Email christian@webwork.com.au Http www.webwork.com.au