Trouble importing photos from Panasonic camera

I'm getting error messages when attempting to transfer photos from my Panasonic camera to my Mac. Details:

* Running Lion 10.7.4 on MacBook Pro

* iPhoto '09 version 8.1.2

* Brand new Panasonic DMC-ZS20

* SanDisk 4 GB SDHC card, which I formatted using the camera function when I first installed it

This was my first weekend with the camera and I went out and shot 300+ photos. Used the USB cable that came with the camera to hook it up to my MBP. On the camera screen I selected the "PC" option. Camera disk appeared on my desktop and iPhoto loaded. iPhoto recognized the camera and displayed all the photos correctly. The problems happened when I tried to import them. I selected "Import All" and the first few 4 or 5 imported OK, and then it just hung there (little spinning circle and one photo file name displayed). Finally after a few minutes, I got the error message "The disk was not ejected properly" even though I hadn't touched the camera or cable. Photos that managed to import were fine - no corruption. Steps I took to trouble-shoot:

* Tried reconnecting to iPhoto and this time importing them one at a time. This worked for a few and then again, it go hung up. Thinking there might be an issue with one particular photo being corrupted, I tried different photos from different parts of the disk. There seemed to be no pattern to the issues. A photo would hang one time, but then import fine the second.

* Thinking it might be an iPhoto issue, I quit iPhoto and just tried to drag photos from the camera disk directly to a folder on my hard drive. I was able to open the camera disk and locate the photos (file names were like P1000150.JPG). But the same things happened when I tried to copy them to my hard drive -- a few would copy and then it would get hung up. I got system error messages -36 and -43.

* I tried restarting my computer and restarting my camera.

* At one point my camera got so "confused" that it wouldn't turn off, or even recognize that I had unplugged it. I finally had to take the battery out to reset it.

* Thinking it might be an issue with a faulty SD card, I loaded the card into my printer's card reader and was able to transfer all photos without any problems. Photos look great.

* In a possibly related issue, I tried to load the GPS data from the CD that came with the camera to my SD card, but it the GPS data would not load. Even though the card was empty (this was the day I got the camera, before I took photos) it kept telling me it needed 1.6 GB of space and I only had like 45 MB available… I'm typing these numbers from memory, not sure they are exactly right, but the point is that I had an empty 4 GB card and there should have been plenty of room.

So, is there anything else I can try here? Has anyone else had problems with Panasonics and Macs? Could it be an SD card issue, even though it worked fine in the other card reader? Or do I have a defective camera and need to send it back?

Thanks,

Jill