Help with java error

["Smith, Mike" <Mike_Smith@xxxxxxxxxxxxxxxx>]

Hi, 
I have 2 vendor products that both use Java and both have started
receiving the following error in the last week or so.  
com.ibm.as400.access.AS400SecurityException: Password is not set.  
 at java.lang.Throwable.<init>(Throwable.java:195)                 
 at java.lang.Exception.<init>(Exception.java:41)                  

I have been working with 1 of the vendors to resolve, but we have come
up with the answer yet.  I just discovered the 2nd issue a few minutes
ago.  
I've gone
here(http://www-1.ibm.com/servers/eserver/iseries/toolbox/faq.htm#faqT)
but I just don't know enough about java and classpaths to get this
resolved. 

Can someone tell me what and where to look at to troubleshoot this.  

I'm on V5R4.  I also have 5722JV1 Java Developer Kit 5.0 installed. 

Thanks