Assembler failing after form saved using ES3 designer(original works saved using ES2)

I am having an issue with a form that was created in ES2.  If you use the form created in ES2, the assembler process works fine.  Once you open the form and save it using ES3, the process fails.  Any idea what to look for, or anybody else see this behavior?  I have also created a new form using the the old form as a template and it also fails.