Hi,

It seems most likely that you have a faulty CCD sensor.

Here is a link to a video that shows how to replace the CCD sensor in your camera. It is in German but the video is self explanatory.

https://www.youtube.com/watch?v=coM_V7kg...

Here is a link to a supplier of the CCD sensor. It is not a recommendation to use the seller, it is merely shown to give an idea of the cost of the part and a close up view of what it looks like. There are others online that may suit you better. just search for panasonic lumix dmc-tz3 ccd sensor

http://www.ebay.com/itm/Original-New-ima...

Hopefully this is of some help.