corrupted prefs files

I ran verify preferences in Onyx and it came back with /Users/***/Library/Preferences/com.apple.iphotomosaic.plist:
Conversion of data failed. The file is not UTF-8, or in the encoding specified in XML header if XML., so I looked it up in it's help and it recommended to delete the file... I tried looking for instructs on the net but there really isn't a simple explanation (I was also confused by the advice to be careful as deletion of some prefs may cause some progs to not work!). I assume that Onyx doesn't fix problems but just finds them. Does Macjanitor fix them? or is there a free prog that does this (cause obviously disk utilities isn't doing it either). I don't mind manually doing it myself but the instructs I have been able to find just end in me having to use a 'translator' hehe and googling almost everything tofigure out what and why I'm doing something.

Can any one help me with this one?
Thanks in advance...

I'd just delete the file. It will be de recreated at boot.

Make sure your application is closed. Just drag the preference file to your desktop. Launch the application. A new preference file will be written. If it performs as expected, you can delete the file from the desktop. If not, you can return the file to the preferences, overwriting the new one, and you are where you started.

Ahhhhh thanks jroller. Many thanks! I'll give it a try