ichat insufficient bandwidth

i am trying to do ichat with my friend who is on her macbook. we usually always do ichat and it works perfectly (i'm on a windows computer and she's on a macbook) how can i fix this? it's driving me insane because it usually works but the last couple of days it's been saying 'ichat insufficient bandwidth'. now, she just tried doing video with another friend of ours who has a macbook, also, and it worked perfectly.. so is it my computer? if so how the heck can i fix it?

More info needed here - you say iChat - on windows? or is it Skype. Bandwidth can be a function of someones connection - yours or hers - internet supply. Also if it is just iChat the ports used during the 3 way handshake and resulting attempt to connect can be an issue. So DSL or Adsl or Cable become a factor in hunting down the problem and are both participants at home or hooking up thru a LAN. If u are doing a cross platform chat use Skype on both as it will find more open ports more easily.

If u continue having problems setting up a video chat, try just audio as it uses far less bandwidth and will help with troubleshooting your issue. iChat on the Mac uses the same 3 way handshake to initiate the audio chat so if it really is an internet issue then audio should be easily established.