In GoBinder paper types are defined in xml-files.
To remove some of them, go to %programs%\Agilix\GoBinder\PaperTypes and delete/remove the corresponding xml file.
If you are not shure wich one to delete, open them with a text editor or Internet Explorer and look for the line
<paperType ... displayname="xyz" ...
where "xyz" is the name you see in GoBinder.
Restart GoBinder and the paper(s) should be gone :-)