Registry knots

I modified a portfile by adding a tilde to the port name: transcode-1.1.0~cvs20070718 macports built the port, but got confused during the installation, so that now I get the cheerful $ port installed Error: port installed failed: Registry error: transcode @cvs20070718_0+a52dec+faac+freetype+imagemagick+libdv+libogg+libsdl+libtheora+libvorbis+libxml2+x264+xvid not registered as installed. No ports are installed. As you can see, it's truncated after the tilde, and then gone into knots. How can I untangle this? It would not be a disaster to start afresh, but if there's a simple solution let me know. Dave