I think that caramel vienna must be "cara vienna" which is a light crystal malt, similar to crystal 40 L. Vienna malt is a base malt, like 2-row malt. They aren't even close to the same thing.
If you can't find Vienna malt (and every homebrewstore should have Vienna malt), you might be able to use Munich malt instead. What is the recipe? We can help you find substitutions.