The OpenPnP folks have encountered similar issues with USB and cameras than some LitePlacer users. Jason (Jason von Nieda, the guy behind OpenPnP) has written a good page about the issue:
https://github.com/openpnp/openpnp/wiki ... ooting-FAQ.
Also, this thread has good hints and a link to a tool that might help in diagnostics:
https://groups.google.com/forum/#!topic ... 7d9WNn3DhY.