Fonts not loading in Mathematica running in IIS

I am using The .NET/Link for mathematica in my Asp.Net application (running under IIS 7.5) but am having issues where some of the custom fonts that Mathematica uses do not show up.

For example the character Pi doesn't show up. It should look like:

This problem only happens on one particular machine, and only when running it in IIS, if I create this image in a Console App (or even using IIS Express) then the image is created just fine.

For those with some experience with .NET/Link the code I am using to create the images is:

IKernelLink ml = MathLinkFactory.CreateKernelLink();
ml.WaitAndDiscardAnswer();
Image img = ml.EvaluateToTypeset("HoldForm[x Pi x]", 0);
context.Response.ContentType = "image/gif";
img.Save(context.Response.OutputStream, ImageFormat.Gif);
ml.Close();

But I don't believe an understanding of that is a requirement, as I believ开发者_高级运维e its solely an issue with loading the font and using it in IIS.

So, I guess the meat of the question is: Is there any reason that IIS (or any Windows Service) wouldn't be able to read/process a font besides permission issues (since I tried running the service as Admin).