Error while running keytool

when i try to create a signed apk it gives me the following error

Error while running ‘keytool’:
C:\Program Files\Java\jdk1.5.0_10\bin\keytool.exe -genkey -keystore “C:/Users/knight/Desktop/samurai.keystore” -storepass $php0987# -alias cyber -keypass vikashsamota -validity 18250 -dname “CN=vikash samota, OU=cyberlinks, O=cyberlinks, L=new delhi , S=delhi , C=91”
…didn’t generate a new key inside existing keystore!

i have the same problem