Loading Winamp's in_midi.dll from .NET

I am trying to load a Winamp input plugin and work with it in C#. According to the Winamp SDK, this is the proper way to load a plugin:

in_mp3_lib = LoadLibraryW(path);
if (in_mp3_lib)
{
    PluginGetter pluginGetter = (PluginGetter)GetProcAddress(in_mp3_lib, "winampGetInModule2");
    if (pluginGetter)
    {
        in_mp3 = pluginGetter();
    }
}

So I've created a similar code in C#:

[DllImport("kernel32", SetLastError=true, CharSet=CharSet.Unicode)]
static extern IntPtr LoadLibrary(string lpFileName);

[DllImport("kernel32", CharSet=CharSet.Ansi, ExactSpelling=true, SetLastError=true)]
static extern IntPtr GetProcAddress(IntPtr hModule, string procName);

delegate IntPtr PluginGetter();

IntPtr hmod = LoadLibrary("in_midi.dll");
var getmod = (PluginGetter)Marshal.GetDelegateForFunctionPointer(GetProcAddress(hmod, "winampGetInModule2"), typeof(PluginGetter));
IntPtr modptr = getmod();

However, on the line with LoadLibrary, an error (not exception) window is shown:

---------------------------
Microsoft Visual C++ Runtime Library
---------------------------
Runtime Error!

Program: C:\Users\...

R6034

An application has made an attempt to load the C runtime library incorrectly.
Please contact the application's support team for more information.

---------------------------
OK   
---------------------------

And hmod is null.

Apparently, the plugin tries to load msvcrt90.dll, but this error keeps showing even if I have it in the directory.