Error message: A potentially dangerous Request Form value was detected from the client

Hello,
I'm trying to generate an email contact form, including the back-end
VB ASP.NET code using the example on this site:

http://www.ctrfx.com/form/
It all works fine until I submit the form. It generates the following errer message:
"A potentially dangerous Request Form value was detected from the client" which I understand is a security related issue. I have a pro-hosting account at Brinkster. My question is how can i resolve this issue?
My purpose is to incorporate a simple contact form using asp.net which can be send by mail. Perhaps somebody has an example. I appreciate your help.

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