Thanks for the suggestion. I tried using .net 2 but no luck.

I did

C:\Windows\Microsoft.NET\Framework\v2.0.50727>csc /target:library /out:c:\sqlser

versendmail.DLL c:\sqlserversendmail.cs

Microsoft (R) Visual C# 2005 Compiler version 8.00.50727.4016

for Microsoft (R) Windows (R) 2005 Framework...