"Access Denied! Your're address is blacklisted"

I had setup ubuntu 8.04 server w/ispconfig followed howtoforge guide everystep. It work well for a while but now I have complain from my customer who hosted website with my server. Someone cannot login or access PHP page and display "Access Denied! Your're address is blacklisted" (indeed "Your're"). I recommend them to click back and refresh, sometime it pass sometime not. And today I face it myself, my own computer also get "Access Denied! Your're address is blacklisted" when I try to login to my customer website. Does anyone face the same problem like me or has any ideas or solutions plese help. Thanks in advance.

And also this error occured in phpBB webboard too, same message appear "Access Denied! Your're address is blacklisted" when trying to post or login.

 

so do you have any ideas or suggestion. I think that some security modules in PHP (may be suhosin) cause the problem. I have search through google, some people do face the same problem with me, but only a few. (yea, "your're"!)

 

Do you use mod_security, mod_defensible, mod_spamhaus or something like that?

 

Ok, I have found it out. spamhaus cause the problem!

 

If this happens just for one web site, then it seems to be a problem with the application and not the server setup.