Sybase Central cannot register the AMCP plug-in

If you get this message when you attempt to register the AMCP plug-in (amcplugin.jpr):

Could not read manifest.file

The installer has renamed the amcplugin.jar file to amcplugin.jar.installed to avoid overwriting existing files.

When you attempt to run registerAMCP from the command line, you see:

Error: Unable to find the AMC Plugin binary.
Please check that $SYBROOT has been set correctly and that the file
/AMCP/lib/amcplugin.jar' exists.\n

Rename amcplugin.jar.installed to amcplugin.jar.