GC Problems?

Hi I'm getting various reports from users that they are getting randomly logged out when usimg the inbuilt session capabilites of php4, but I cannot replicate the error/problem. I'm beginning to think that it's not a coding error, but maybe a garbage collection problem. /tmp is cleared every night by a simple bash script that removes sesions that belong to yesterday and I've made gc lifetime to 12hrs, but users are still getting logged out [randomly] at anytime within this period. Has anyone else has similar experiences? BTW, I've compiled with --enable-trans-sid. ;php.ini for php4.0.3pl1 session.save_handler = files session.save_path = /tmp session.use_cookies = 1 session.name = SESSID session.auto_start = 0 session.cookie_lifetime = 43200; [12 hours] session.cookie_path = / session.cookie_domain = session.serialize_handler = php session.gc_probability = session.gc_maxlifetime = 43200 ; [12 hours] session.referer_check = 0 session.entropy_length = 0 session.entropy_file = session.cache_limiter = nocache session.cache_expire = 43200; [12 hours] TIA bealers