If you are following the procedure described in Installing an Additional Iguana Server on Windows to manually install an Iguana 4.0 or later server on a system on which Iguana 3.3.2 is already running, you may run into problems with plugins that attempt to interact with the Iguana 4.0 or later server. You may see failure messages that look like this:

Unhandled Exception: System.TypeInitializationException: The type initializer for 'IguanaToClient.Iguana40' threw an exception. --->
System.TypeLoadException: Could not load type 'IGCmessageProcessorOnDisconnect' from assembly 'IGC_csharp, Version=1.0.0.1,
Culture=neutral, PublicKeyToken=8b5b40b01aaef44a'.
at IguanaToClient.Iguana40.set_Processor(MessageProcessor WithEventsValue)
at IguanaToClient.Iguana40..cctor()
--- End of inner exception stack trace ---
at IguanaToClient.Iguana40.Main(String[] Args)

This is because Iguana 3.3.2 registers its .NET interface, IGC_csharp.dll, in the .NET Global Assembly Cache (GAC). DLL files that are registered in the GAC are used in place of those specified in the PATH environment variable. If Iguana 4.0 or later is installed manually, the IGC_csharp.dll file that Iguana 3.3 uses is found first, instead of the IGC_csharp.dll file that Iguana 4.0 or later uses.

	In Iguana 3.3.2, plugins were called client executables.

To resolve this problem, you must:

• Manually unregister IGC_csharp.dll from the GAC. To do this, use Windows Explorer to open the assembly subdirectory in the directory in which Windows is installed on your computer (typically, C:\windows\assembly or C:\winnt\assembly). Right-click IGC_csharp.dll and select Uninstall from the popup menu that appears.
• Copy the Iguana 3.3.2 version of IGC_csharp.dll from the directory in which Iguana 3.3.2 installs it to the directory in which the Iguana 3.3.2 plugins are stored. (Typically, you can find the Iguana 3.3.2 version of IGC_csharp.dll in the client\csharp subdirectory of the directory in which Iguana 3.3.2 is installed.)

	When Iguana 4.0 or later is installed by the Iguana installer, it automatically unregisters IGC_csharp.dll from the GAC, which means that this problem does not occur.

You can also choose to recompile your plugins to work with Iguana 4.0 or later. To do this:

• Compile the plugin using the version 4.0 or later version of IGC_csharp.dll.
• Copy the version 4.0 or later version of IGC_csharp.dll to the directory in which the recompiled Iguana plugins are stored. (Typically, you can find the Iguana 4.0 or later version of IGC_csharp.dll in the plugins subdirectory of the directory in which Iguana 4.0 or later is installed.)