Jaxel - I'm unaware of any problems with the routines. There have been bugs, but every one that has come to my attention has been quickly fixed. If you install my routines, and my online.cgi script, and have a problem, please let me know.
If you are worried about a particular problem, let me know which one. I have fixed the problem of invisible users showing up as "username.inv". I have also fixed a problem where a guest occasionally would be listed as Guest #x () - with no host information. Also, I just added a bit of code that if a person first shows up as a guest, and then posts or gets their cookie set, their guest entry is removed and their name logged in it's place.
And finally, just tonight I added the current time display to the Who's Online page... and if there is no one else around and you don't have it set to include yourself, it displays a message on the Who's Online page instead of just the table headings.