Reflection assembly load error (RuntimeBinderException)

I need to load DLL in runtime and call TXMod.Init()
This exception is throwing every time:

An unhandled exception of type 'Microsoft.CSharp.RuntimeBinder.RuntimeBinderException' occurred in System.Core.dll
Additional information: Member 'Mod1.TXMod.Init()' cannot be accessed with an instance reference; qualify it with a type name instead

Can you help me?