Outlook Add in not loading on other computers

I have written an add-in for outlok 2003 in VS 2005. On the development computer works just fine but on other computers in the same conditiion does not work. The add-in apperars in the com add-in list, but with the error "Not loaded. A runtime error occured while during the loadinf of the COM add in". I have installed .NET 2.0, PIAs, but still not working.
Can someone tell what dependecies should my add-in contain, besides the following:
Interop.Microsoft.Office.Core.dll
Interop.Outlook.dll
Microsoft.Office.Interop.Outlook.dll
msoutl.dll
Office.dll
?

I even manually add Microsoft.Office.Interop.Outlook.dll, Office.dll to GAC
It has anything to do with the trust of my add in? If this is the problem, then how can I set Full Thrust and for wich dependecies.
TIA