Why do add-ins reference specific path
 

I have built an Excel 2002 add-in that contains a number of UDFs that
users can call from cells in a worksheet.

When I distributed the add-in, I had it installed in the
%APPDATA%/Microsoft/Add-ins folder, where %APPDATA% is the environment
variable for C:\Documents and Settings\usr00000\Application Data\

The problem is that if a user builds a spreadsheet and then sends it to
another user, the worksheet contains references to the path on the
originator's machine (not using %APPDATA% environment variable.)

How do I fix this? Is there a better place to install add-ins so that
excel doesn't add these absolute path references?