Application Attempted To Perform An Operation?

I have a function that finds a files MIME type for download purposes. I use this DllImport:

Code:
[DllImport("urlmon.dll", CharSet = CharSet.Unicode, ExactSpelling = true, SetLastError = false)]
static extern int FindMimeFromData(IntPtr pBC,
[MarshalAs(UnmanagedType.LPWStr)] string pwzUrl,
[MarshalAs(UnmanagedType.LPArray, ArraySubType = UnmanagedType.I1, SizeParamIndex = 3)] byte[] pBuffer,
int cbSize,
[MarshalAs(UnmanagedType.LPWStr)] string pwzMimeProposed,
int dwMimeFlags,
out IntPtr ppwzMimeOut,
int dwReserved);

I use this function:

Code:

#region GetMimeFromFile(string)
public static string GetMimeFromFile(string file)
{
IntPtr mimeout;
if (!File.Exists(file))
{
throw new FileNotFoundException(file + " not found.");
} //if
int maxContent = (int)new FileInfo(file).Length;
if (maxContent > 4096)
{
maxContent = 4096;
} //if
byte[] buff = new byte[maxContent];
using (FileStream fs = new FileStream(file, FileMode.Open))
{
fs.Read(buff, 0, maxContent);
} //using
int result = FindMimeFromData(IntPtr.Zero, file, buff, maxContent, null, 0, out mimeout, 0);
string mime = Marshal.PtrToStringUni(mimeout);
Marshal.FreeCoTaskMem(mimeout);
return mime;
}
#endregion

Locally, it runs fine. However, when I put it on a GoDaddy server, I get the error:

"The application attempted to perform an operation not allowed by the security policy. To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file. "

My stracktrace points to line 256, which is the ending french bracket of my GetMimiFromFile function.