The DMR-HS2 is a 2002 model according to Jeff's Panasonic recorder reference post at the AVS Forum. I have no personal experience with the Panasonic DMR-HS2 or other Panasonics of that vintage.
My Panasonic experience begins with the 2005 models.
The following observations are based upon 2005 and newer models. It is most likely that these more recent Panasonics share a number of DVD Drive design characteristics with earlier models.
If your DMR-HS2 model's DVD Drive was recently opened for routine cleaning of the lens and hub/spindle, was the roller/slider at the rear of the disc tray positioned to the far left as shown in the first photo? (The photo shows a 2005 model DVD Drive.) In order for the disc tray to function properly the roller slider must be positioned to the far left so that it will run in the guide channel on the underside of the DVD Drive lid.
Misalignment of DVD Drive operating mechanisms may occur when the disc tray is extended while the drive lid is removed. At the AVS Forum I've posted detailed descriptions and photos demonstrating procedures for correct realignment and reassembly of 2006 and newer DVD Drives with those problems. This post and the post following it describe the procedures:
To view the photos attached to those posts one must register at the AVS Forum.
Another possible problem is wear to, or failure of, the rubber belt that is part of the DVD Drive disc tray open/close mechanism. The second photo shows this belt running from the large white wheel to the small white wheel just to the right as seen toward the bottom center of the photo. (The photo shows a 2006 model DVD Drive.) If belt replacement is needed the disc tray will need to be removed to gain access to the belt. Since 2005 and older DVD Drives differ from those in 2006 and newer models the linked post should be viewed as a general guide but may differ in reassembly/realignment details.
As to a "kit" I'm not sure what might be included; perhaps just the rubber belt and instructions as to it's replacement. The belt itself may be of generic design and purchased at a nominal cost. If the belt is the problem the major expense is the labor to open, disassemble and reassemble the DVD Drive.