What is the format?
I don't know about panasonic, I have an JVC Everio that uses the .MOD format. Premiere Pro does not like .MOD. However Pinnacle Studio 11 and up does. I picked up a copy of Studio 11 basic for $50, I use it convert my video files, it re-encodes it better than any of the free converters I have tried. Also if you go into premiere pro cs4, in the help section located under the About menu, you can search for supported import and export formats. If that does not work, just take a trip to your located book store and find the Premiere pro classroom in a book, Not saying you have to buy it, Just look it up in the store
( I do that a lot, especially when you haven't got a lot of money to spend on expensive books), Your local library might have a copy too.