maybe using an older version of cpkcr.exe? i have had similar error and redownloaded the v1.4 version of cpkcr.exe. though i am using a portable java the gui works fine for me now with updated exe file.
just incase somebody needs it, i've uploaded my portable version of java 1.6 environment. you can start any java app without installing any java environment.
just put the .jar archive and all other files in the directory of the portable java and edit the start_app.bat with windows editor right click. put for "X.jar" the app you want to start, for example cpkcrgui.jar or the other one cpkforpgui.jar