Limited In Establishing an A/V Connection Using New 2008 Mac Pro 8-Core

Question

I will apologize in advance for the long and complicated story that follows.
I purchased this 8-core Mac Pro two weeks ago. I installed all software fresh on the Mac Pro and transferred no data from an iMac I had previously been using. The Mac Pro was running fine and I was able to have a video iChat with one of my friends across town who has a mid-2007 iMac with no difficulty. I had initially set up my Mac Pro with file sharing turned on so that I could exchange files with my wife who took possession of my mid-2007 iMac. A few days went by and my wife decided to turn off file sharing on my Mac Pro. Suddenly my Mac Pro would not boot at all, showing the spinning black pinwheel and the silver screen with the Apple logo for more than 30 minutes. I tried to repair permissions on the Mac HD, but I got a red error message that the permissions could not be repaired. Interestingly enough Verify Disk ran and report no problems with the Mac HD.
At this point I did a full erase of the Mac HD, and did a complete restore from Time Machine. After a few minor changes like having to reimport my e-mail, my Mac Pro seemed to be working fine again. However, today I received a iChat video invitation from my friend across town, and when I responded, I soon got a "failure to establish communication" message. I then tried to establish a video chat with my friend. After watching the spinning black wheel in the iChat dialog (which had good video), I soon got the same message. He also got this message on his end. We were able to establish Text Message communication through iChat, but we could not establish either video or audio. My friend's Mac was working fine in iChat because he had just been iChatting using video with one of his friends. The problem thus was firmly on my end.
At this point, I tried to video iChat from my Mac Pro with my wife in the next room on her iMac. It worked perfectly and we had both good audio and video. However, every time I attempted to iChat with my friend across town with, I always soon received the message that the connection could not be made bacause my friend had not responded, which of course, he had.
I deleted all of my user preferences related to iChat (four if I recall correctly) but this did not help.
In summary, I have limited use of video iChatting from my Mac Pro only with my wife next door on her iMac. Incidentally, I went over to her iMac, logged on, and instantly had a video iChat going with my friend across town.
I have just spent 3 hours on the phone with Apple Suport and went through several layers of tech support. In the end, their only recommendation was to do a complete erase and reinstallation of the OS. I am not willing, at least at this time, to do this since I have every one of Apple's Pro software applications (FCS2, Aperture, Logic PRo 8 Studio, etc.) installed on this machine and it takes a long time to reinstall all that software.
I would be extremely grateful for any suggestions that anyone may have.
Tom

Answer 1

I finally solved this problem by doing three things. I do not know which of the three really solved the problem, but one of them did. Since this is a new Mac Pro the weekly and monthly maintenance routines had not been run. I ran them using a widget called Maintidigit. Second, I reinstalled iChat directly from the Leopard install disk. Third, I rebooted my cable modem (Road Runner) and then I rebooted my Buffalo Router and while power was off to the Buffalo Router, I unplugged and then plugged in all cables to it. I then plugged in the power cable. Video iChatting with my friend across town worked perfectly with no error messages after these three changes.
Tom