JNLP file missing and "Unable to launch the application" error

Hi

We have one issue on Windows Vista(64 bit processor) system.

Our software (swing application) is installed on the system using java webstart 6. (client has JRE 1.6_0_10 version,Tomcat 5.0 is pointed to 1.5_0_14)

there were problems when there are updates.

When the user tries to login to the software using shortcut, an application error message "Unable to launch application" is shown.
When checked , it is observed that JNLP is missing. We are sure that it is not deleted manually.

Did anyone come across with such an issue?

Please help me..

Thanks,
Chakri.