Java 5.0 Security

When I use Java 5.0 on the client machine with with either 1.4 or 5.0 on the server I can’t get the client to log on. The message I get is:

An error occurred while launching/running the application.

Title: Servoy Client
Vendor: Servoy
Category: Download Error

Could not verify signing in resource: (http://149.142.139.100:8080/lib/j2db.jar, 1107742409357)

Windows
using build 319