Quick Solutions
1) Turn the camera off and on!
2) Make sure you are using the Mini-USB to USB cable provided with your camera. Check that this is plugged into the camera and to the "Camera" opening on the USB Hub.
3) Turn on and off the camera and/or replug the Mini-USB to USB cables in. This is usually the solution if you closed DSLR Remote Pro for some reason.
4) Make sure there is only one copy of DSLR Remote Pro is open. There is a chance that you clicked the icon too many times and multiple instances of the program are open. Only the first instance will be able to connect to the camera - the rest will not be able to.
5) Restart the computer
Complex Solutions
USB cable: Excessively long, damaged or loose USB cables can cause problems. If possible use the USB cable that came with the camera and plug it in directly to a USB port on the computer. Ensure the cable is not damaged and is firmly connected at both ends.
PRINTER ERROR: If your printer is experiencing a "Printer Error" it might be interfering with the connections for the rest of the ports. Fixing a printer error can be solved by calling Imaging Spectrum - 214-342-9290
USB hubs: Since ours is a self-powered USB Hub, it might be getting too stressed out if you are using all four ports at once. Since the "USB" port is not necessary I would take it out during photobooth use.
Camera power supply problems: Some cameras may become unreliable as their batteries begin to run down. This is more likely to be a problem when using live view as this uses more power than normal camera operation. If you did not get an AC Adapter for your camera we suggest you get one as soon as possible.
Camera overheating: The camera's sensor may get too hot if live view is used for long periods of time and the camera may shut it down to prevent damage. If you're running a photo booth you can put it into standby mode when not in use by pressing F6. This will turn off live view and allow the sensor to cool down. Press F6 again to return to the ready screen with live view enabled.