php safemode woes

Hi all, i am running a php script with script owner say x (uid = 501) with safe mode on. php version 4.2.2. i am generating some temporary files in the runtime with tempnam() and storing them in a in temp directory . but the script cant access the temporary files in the temp dir as they are created with rw------- permissons for user apache.the temp dir has 777 permissions set. also it gives me an error saying that safe mode is on, the script owner whose uid/gid is -1/-1 is not allowed to access the file with uid/gid 48/48 interestingly the uid of the script is not -1 and there is no such user with -1 as uid . can anyone help me abt whats wrong with the script or setup ? or is it a bug ? kindly enlighten, regards, KM