Workflow error

Migrateduser

Hello, We are currently setting up or server with TeamSite version 7.5 Wwe have set up a very basic workflow, but when trying to invoke the workflow with new job we are getting the error "Could not initialize class com.interwoven.modeler.util.ModelInstanceUtil". Does this happen because we are missing some packages. Please suggest on this if anyone has faced similar issue. Thanks, Felicia