Ok, could be a number of things. Do you have a console, either wired or netconsole attached to the cRIO to see if there are any errors or if the camera task is dying?
If you connect the camera to a PC with IP 192.168.0.xx where xx is anything but 90, and you use a browser to connect to
http://192.168.0.90 do you see a live image from the camera? If so then you know the camera is working so then you need to look at the code.
Also I assume the LEDs are lit on the ports on the cRIO when the camera is plugged in and the light around the lens of the camera is green?