Video and Voice Problems

Hi. I have just upgraded to trillian pro 3. And I just bought an A4Tech webcam. i can see myself on the right window but when i invite a friend to view my cam they can’t see anything. 3 of my friends on yahoo accounts couldn’t view my webcam. And one of my friends invited me to view her webcam, i accepted but i couldn’t see her webcam. So i switch to MSN messenger (not trillian) to check but also it did not work. I couldn’t even see myself on msn. I know my webcam is working fine because i can see myself on my own computer.
I was on another wireless network and couldn’t access voice chats as well. And another thing is i cannot transfer files using trillian. it never connects.

I am using a Linksys wireless g router with a cable connection. But i’ve also tried transfering files using a dsl connection and it still doesn’t work. I’d appreciate any help that you guys can give me. Thank you in advance