Check your OS X firewall settings (System Preferences->Security). Turn off the Firewall and then try. Plus if you are going through an internet router make sure you open the logical ports for iChat list in the Apple document "Well Known" TCP and UDP ports used by Apple software products.
Good Luck.
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PowerMac G5 Dual 1.8(Rev A.), , 7 Gig RAM, Pioneer DVR-110, ATI X800XT, OS X 10.4.11 & 10.5.4, 23'' HD LCD
Mac Book Pro Core 2 Duo 2.16Mhz, SuperDrive, ATI X1600, 2GB RAM, OS X 10.5.4
Tibook 400Mhz, DVD drive, 1024 RAM, ATI Rage, OS X 10.4.7
1TB Time Capsule
5g iPod 30Gig White |