"ImportError: No module named deserialize" when launching ur5_bringup.launch

edit

When I attempt to run the command roslaunch ur_bringup ur5_bringup.launch robot_ip:=172.22.22.2, I get the following output:

... logging to /home/rkeatin3/.ros/log/5d470f28-5de0-11e4-aa81-fc4dd43d9838/roslaunch-dscl-rosstation-02-13666.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://dscl-rosstation-02:45140/

SUMMARY
========

PARAMETERS
 * /robot_description
 * /robot_ip_address
 * /rosdistro
 * /rosversion
 * /tf2_buffer_server/buffer_size

NODES
  /
    robot_state_publisher (robot_state_publisher/state_publisher)
    tf2_buffer_server (tf2_ros/buffer_server)
    ur_driver (ur_driver/driver.py)

auto-starting new master
process[master]: started with pid [13683]
ROS_MASTER_URI=http://localhost:11311

setting /run_id to 5d470f28-5de0-11e4-aa81-fc4dd43d9838
process[rosout-1]: started with pid [13696]
started core service [/rosout]
process[robot_state_publisher-2]: started with pid [13708]
process[ur_driver-3]: started with pid [13726]
process[tf2_buffer_server-4]: started with pid [13727]
Traceback (most recent call last):
  File "/opt/ros/hydro/lib/ur_driver/driver.py", line 19, in <module>
    from deserialize import RobotState, RobotMode
ImportError: No module named deserialize
[ur_driver-3] process has died [pid 13726, exit code 1, cmd /opt/ros/hydro/lib/ur_driver/driver.py 172.22.22.2 __name:=ur_driver __log:=/home/rkeatin3/.ros/log/5d470f28-5de0-11e4-aa81-fc4dd43d9838/ur_driver-3.log].
log file: /home/rkeatin3/.ros/log/5d470f28-5de0-11e4-aa81-fc4dd43d9838/ur_driver-3*.log

I've been unable to find any posts with the same answer. I checked the roslaunch log file, but it doesn't have any more useful information. Any ideas?

Edit: I'm using hydro, installed from debs.