I have written a simple Excel automation add-in using c#. It works
fine on my WinXP PC, but does not work on my MediaCenter PC. The
sympton is that the add-in is shown in the add-in list but all the
functions are not available (i.e. when you open the function help
dialoug, these functions are not displayed, actually even the assembly
is not shown in the category.)

I have tried (1) recompile the code on the MediaCenter, (2) manually
register the code compiled on XP, (3) run a setup program created using
visual studio. None of them worked.

I guess there may be something specific on the MediaCenter machine or
some Excel configuration (e.g. security etc). But I just couldn't
figure it out. Any suggestions and recommendations, or even wildest
guess, are welcomed.

My environment: Visual Studio 2005, Excel 2003