Agni,
Thanks for your prompt feedback. Is it any possible way for a normal user (not pose any administrator right) to fill out the form without this type of error.
I am doing so becasue of the user right restriction onto the share point. Will this be solved if i allowed full trusted on the web services calling?
I have tried to create another new simple form (without any web services or code behind) and upload to the share point and i still getting the same error.
Your advise is highly appreciated.