If you have lost the disk, it seems impossible to get a new one from Panasonic. Others have tried and failed. If getting HD Writer to run is not possible, my personal reccomendation is Adobe Premier Elements. Be sure to get version 11, as that is the one with full AVCHD support, including 1080p60. If you do have a lot of 1080p60, Premier Elements needs at least a medium strong computer.
"I heard that not all Blue Ray players will play the transfer. Is this true?". Yes. I have a Panasonic, Sony and Samsung BD players. They all have their quirks. If you are shopping for one, look had at the Panasonics. Part of their marketing play is to make it easy to play videos taken on Panasonic cameras. There is a slot in the front for your SD card. Take it directly from the camera to the BD player and run it with the remote. All three work well with Blu-Rays created by Premier Elements 11 burned on my laptop's Blu-Ray burner, even the 6 year old Panasonic.
Each of us has our own experiences. Many like the Sony software a lot. I tried it and may be the only person on earth that had trouble I couldn't fix. I switched to Adobe and have not looked back.
If you look in the lower left corner here, http://muvipix.com/pe11.php
you will see a free 8 part video tutorial introduction to PrE11 buy Steve Grisetti. The same guy does a detailed tutorial for PrE11 here at, Lynda.com - PrE11
One of the very good parts of HDWriter is how it can organize you video files. PrE11 comes with a program called "Organizer" that works very well at keeping your files in places you can find them. It will also automate the transfer of your videos from your card or camera, much like HDWriter.
But, please, make some backups before you take any of my advice.