Helpreobfuscate error (annoying)

i've been working on my client for a week
i ran cleanup.bat
decompiled
replaced the src with my backup
recompiled then reobfuscate and get this error

i repeated that method 4 times and still the same error -___-

Do you have a duplicate class entry...?

Don't understand, you ran cleanup.. Are you updating your client from 1.2.5 > 1.3.1?

Does the jar run when unobfuscated?