sigcheck shows n/a in several fields for nbexec.exe

$ sigcheck -m -q "c:\program files\java\jdk1.6.0_34\lib\visualvm\platform\lib\nbexec.exe"

c:\program files\java\jdk1.6.0_34\lib\visualvm\platform\lib\nbexec.exe:
        Verified: Signed
        Signing date: 6:26 AM 6/21/2012
        Publisher: n/a
        Description: n/a
        Product: n/a
        Version: n/a
        File version: n/a
        Manifest: ...