time out if someone walks away

Hi,

1. I am using SA for logging in and securing pages. How would I set a timeout if a user walks away from their computer so they are logged out automatically?

2. How else can I make the pages more secure in addition to page access with SA?

3. I also had an issue with SA messing up my files by adding line breaks and random code into mySQL table associated with the files I was trying to protect with SA page access. Then I tried to reload a backup of the same files with DW CS3 and still had the same issue so some of my webpages where not showing, and it added some random text to mySQL table, each line is in a different column on the same table row though. [] = a small box

if(!WA_Auth_Rule_Passes("administrator")}{
[]WA_Auth_RestrictAccess("../accessdenied.php");
}
?>

I had 12 rows of this same code in mySQL, never had this issue before, is this a known issue? How can I prevent this?

thanks