I presume you went to this page click here to contact them. Their site is 2008 registered and to my knowledge they are still in business.
Registration codes can be awkward. They generally require you to enter them as they were produced, so if the `Caps Lock` was on for the capitals you will need to use it rather than `Shift`. If you have a copy that was provided by them in an e-mail or whatever, it is safer (and easier) by far to copy and paste it.