Failed RSA-signed pages Java 1.4.2

[Michel Gallant]

Have there been any changes to security model for
RSA_signed jar archives and JavaPlugin which would cause
lots of these:

"Warning - Security" dialogs
Certificate Not Verified
Code will be treated as unsigned

with details:
java.security.cert.CertificateException: Check leaf key usage failed in certificate
at sun.plugin.security.TrustDecider.isAllPermissionGranted(Unknown Source)
.....

??

Many JavaPlugin pages have stopped working (but not all). It is not
related to the issuing CA, since I have some that work without (test
certs) with unrecognized CA or that have expired.

Any ideas?

Thanks,
- Mitch Gallant