You may have an older version of the plugin-- there were two different ones, one for 6 and one for 7. It's also not supported under Lion. You should maybe consider Content Browser or XDCAM Transfer. All the existing XDCAM plugins have been replaced by Content Browser, and if you don't want to purchase a CB version 2 serial (20.00) you can still use version 1.1 for free.
XDCAM Transfer is also discontinued but has been tested under Lion and operates normally. Look under 'Legacy Applications' at our main download site-- http://www.sony.com/xdcam-downloads