entered Coupons showing not valid...

hi sir
please help me out to enter coupons code valid in event booking..
i enteret some coupon codes for all events and now i am using that codes in front end event registration form.there is displaying message that.." the coupon entered is not valid..
please help me out for this..or please expalin the way how to add coupons for events with 100% discount .i have all set but i am getting not valid message..why this is happening ..where i have put wrong..?

Hi

What version of the extension you are using ? Could you please submit a support ticket sending us administrator and FTP account of your site so that we can check it for you ?

Regards,

Tuan