Create vertical text for my site.

I found this code surfing the web (http://www.codeproject.com/KB/aspnet/VerticalTextImageCreation.aspx) and I decided to use it on my site.
The problem is that it does not seem to work.
If I use this code to a local site it works fine.
But in my web server it does not even produce the images (the directory is empty).
Any ideas?
Thank you very much.
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