PHP mbstring package Your internal characater set is ISO-8859-1
Warning!

Setting mbstring.internal_encoding to UTF-8 in your php.ini file is recommended to insure accented and multi-byte characters function properly.

I'm not sure why this is being changed, again. I use UTF-8. Is the default of this file different and being reset back when updated?

It is not being changed again. UTF-8 is what you should be using. However, it would appear that your PHP is not using UTF-8 but rather ISO-8859-1. Thus the warning. This will not impact you unless you are using characters with accents such as š or Ø (or maybe a whole bunch of others.)

Should I set somthing on my web host server to rid the error? I may have reason to use French characters.

I may have reason to use French characters if you intend to use them in the names of images or albums as stored on disk, then you will have to set this option. If you are planning on allowing your gallery to run in the zenphoto French translation, by all means this must be set.

If it is just in descriptions and titles it won't be a problem.

I have the same problem of; PHP mbstring package Your internal characater set is ISO-8859-1
Warning! Setting mbstring.internal_encoding to UTF-8 in your php.ini file is recommended to insure accented and multi-byte characters function properly.
But where should I find this php.ini file? Please help!!!

Maybe your webspace account does not allow to change that at all. If you don't know you please contact your ISP.
If you are not planning to use characters as mentioned you can acutally ignore this warning.

This is another thing that should be made a little more clear for newbies like me when going through the error messages for this setup.

Sorry, but what is unclear about the statement that accented and multi-byte characters might not function correctly? Certainly if you need those characters (not everyone does) then you need to figure out how to change this setting. If not you can ignore it.