[Ti] is iChat different from Yahoo Messenger, MSN etc?

[Dr Trevor J. Hutley]

Finally I have a DSL line here in Saudi Arabia, and a wireless router  
for my Al-book to communicate with.  All services are full  
operational, EXCEPT iChat !!!

I was hoping that iChat would now work, with this DSL line.

It works perfectly in Switzerland, but as soon as I get to KSA, nothing.

It has been like that for 2 years, so nothing to do with versions,  
updates, etc.

What is embarrasing now is that my friend, using his 17" block-of- 
concrete laptop (Dell) is sitting by my router and happily using MSN,  
Yahoo Messenger to chat with people all over the world.

Does anyone know if iChat is configured in some way that could  
explain why the software integrated in to the OS on a Mac does not  
work yet 3rd party software in XP is just fine??

I REALLY would like to get this resolved.

Any idea where to start looking for an explanation or finding a  
solution.

regards,  Trevor