Normally the error would be more like "Unable to access jarfile C:\Program Files\Primavera\Project Management\Claim Digger\prm-cd.jar when launching Claim Digger"
If that is the fill error message you are getting then it is just because it is looking for a folder called Claim Digger that is currently named Schedule Comparison. To fix this you just need to rename the folder Schedule Comparison to Claim Digger.
If the error message you are getting is cut off at C:\ then it is possible that the registry entry is currently incorrect.
I only have P6r8 and they have changed the registry for this area of the product but you should be able to go to Regedit and go to
HKLM\Software\Primavera (if you are on a 64bit operating system then it will probably be HKLM\Software\Wow6432node\Primavera).
Hunt through the subfolders and there should be one in there called Claim Digger that has a parameter for the location of the jar file - set this to the same as the path's i've shown above (confirm exactly which one you have currently).
After that change is made, start P6 again and try claim digger again.
as Alex mentioned it seems that your registry keys are not correct. Check the following Path KEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Primavera\P6 EPPM\Shared\External Applications\Claim Digger and check there the key Application and Parameters.
Application ==> %JAVA_HOME%\bin\javaw.exe
-Dprimavera.bootstrap.home="$BREBOOTSTRAPFILEPATH" -Djava.ext.dirs="D:\Oracle\p6professional\EPPM\Java\lib;%JAVA_HOME%\lib\ext;%JAVA_HOME%\jre\lib\ext" -Dapi.schedulecomparison.brand=$SCHEDCOMPAREBRAND -Duser.region=$COUNTRY -Duser.language=$LANGUAGE -Dlogin.dbName=$CURRENT_DBNAME -Dapp.name="$APPNAME" -jar "D:\Oracle\p6professional\EPPM\Claim Digger\prm-cd.jar" "$USER" "$ENC_PASSWORD" "$PROJECT_IDS"
Do you have the JAVA_HOME environment variable set?
Another problem that is possible, depending on the P6r8 version is that the folder Claim Digger is named as Schedule comparison.