What IP address does your laptop have when connected via cable?
What IP address does your laptop have when connected via WiFi?
If I read correctly, you said you can connect to the camera when your laptop is plugged in, but not when your laptop is connected via WiFi?
My first guess is that your laptop is ending up on a different subnet (e.g. 192.168.1.x compared to 192.168.0.x) when it's connected wirelessly.
A temporary solution might be to try to access the cameras over an Internet interface rather than through the internal network. (What type of cameras are they? Are you viewing them through the direct IP interface by going to, for instance, http://192.168.0.127 in a web browser?)