Hey, you know too about asp.net security?

I have a web system that load in RUNTIME a custom dll writen by customers. This run under Win2003 (in winxp no problem), but not permit that... But if i compile the dll in memory, i can get this. So is a file security problem i think...

This a link for past questions on it if you can help:

http://www.google.com.co/groups?q=DLL+author:mamcx&hl=es&lr=&ie=UTF-8&oe=UTF-8&selm=015e01c347e5%2431d4fa30%24a601280a%40phx.gbl&rnum=2