Javascript problem

yo,
 
 i'm making a digital city and now i used a javascript
 that popsup a help window on mouse over! i didnt wrote
 it my self, so i cant see what the problam is.
 
 This is a dutch page.
 
 what is does rong:
 
 1*    if i move to fast from one to another link
       it wil try to close the first window, but
       i moved it fast and the second link used the window
       so it gives a close window error.
 
 2*    Netscape sometimes quits whis the message
       Runtime error and then Pure virtual function call
 
So when you move to fast betueen the links netscape wil
crashhhh!!!!!!!!

The page is calld Groningen.com and it is not yet realeasd
dir is  :     http://www.rcg.nl/users/daniel/danieledensgroningenpuntcom
 
 Thanks in advance and please not mail me troug the site but
 mail me on this adress dedens@pi.net
 
 Daniel Edens
 Girl friends homepage (cool) http://www.rcg.nl/users/daniel