Files Cannot Open ...error Message


I have an emac that runs os x 10.2.8 and is an 800mhz powerpc g4.

I recently purchased Tiger to install but it will not complete the installation. On advice from my brother, I used a program downloaded off the web to clean up my preferences. Tiger will still not install, but the computer works fine other than a couple of issues.

All of my icons changed to either blank folders or what i call the "appleworks icon" with paper,pencil,ruler, and paintbrush.

The other issue, and most important, is that when i try to open a file - jpeg, mp3, dmg, etc. - I get an error message that I cannot find the meaning to on any site I've checked. The message is "The operation could not be completed. An unexpected error occured(error code - 10822)"

Do you have any idea what this means and what I can do to fix it?

Thanks in advance,