Problem on Jar-Signing (URGENT)

Hi all.. I am new in Java/J2ee. Please help me to solve my problem.

I have to do jar signing of the Jar file for my application. For this I have written one ant script.
With this I am able to sign the jar file but on verify it is giving �java.util.zip.ZipException: The system cannot find the file specified�

[echo] Inside verification
[exec] jarsigner: java.util.zip.ZipException: The system cannot find the file specified
[exec] Result: 1

Where as on simply running jarsigner -verify dbm.jar (to verify the jar file) on command prompt.
jar verified. Message is coming. (It means my jar file is successfully signed.)

After this deploying the application in server and then login I am getting this exception.

java.lang.SecurityException: class "com.dbm.flow.demo.ProductMapping"'s signer information does not match signer information of other classes in the same package.
Please help me to solve this issue. Its urgent..
Thanks.

That sounds as if the paths are not specified correctly in the Ant script. What is the directory layout, and what does the Ant task look like?

As to the SecurityException, are you using the saem certificate to sogn all jar files? Are there maybe some files that have been signed differently?