I've added your library to web service and when I try to load anything from the site with your .NET Assembly DLL installed I get the following error loading the page in the browser. If I simply remove your library from the application folder, I don't have an problems. It looks like some sort of permission thing. What permissions are required to run your library on IIS?
[PolicyException: Required permissions cannot be acquired.]
System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Boolean checkExecutionPermission) +7613091
System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Int32& securitySpecialFlags, Boolean checkExecutionPermission) +57
[FileLoadException: Could not load file or assembly 'ChilkatDotNet2, Version=220.127.116.11, Culture=neutral, PublicKeyToken=eb5fc1fc52ef09bd' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
The Chilkat .NET Assembly is a mixed-mode assembly, meaning that the inner core is compiled to native code (because the Chilkat software is written in C++, and the same internal implementation is used across all programming languages and all operating systems).
Here is a link with information to help resolve the problem.
Also see these two links for what was written about it in 2006/2007 (Wow, that was 10 years ago already..)