I was invited to join an exhibition. I'm not really interested to go but I don't know how to reply but still..

Question

...polite. Can you please help me? Do you have any good, businesslike, formal reasons to refuse the invitation? The invitation is below:

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On behalf of the supporting organisations, we would like to invite you to join the 8th presentation of PowerAsian 2007 Exhibition and Conference in Japan........make an early decision to maximize your participation and expand your business by accomplishing the Reply Form.

Answer 1

Thank you for your invitation.
Much as I would like to attend the presentation, I regret that the dates coincide with a couple of meetings I have already scheduled with the Government officials here to discuss our application for grant of tax exemption to the company. I have to also report to my Board of Directors immediately thereafter, the developments in this regard.
Hence it would not be possible for me to accept the invitation which you have so thoughtfully sent me.
If you happen to organise any other similar function which you feel would be mutually beneficial, do please note to let me know.
Thanks.

Answer 2

I am sorry that I must decline your invitation as I have prior obligations on that particular date.
Thank you, however, for including me in an such an exciting event.
Best Regards,
Ms. Fibber