The write and close session functions that you
declare with session_set_save_handler() do not
allow for direct print or echo output.  The 
example from the manual fails to output as shown, 
but the functions do work properly otherwise.  

http://www.tapinternet.com/~mark/phpsess.txt

is the source to a script that fails to do a simple
print "Hello ..\n";
from inside the write function.  The script works 
otherwise as you can see by visiting

http://www.tapinternet.com/~mark/phpsess.php3