You are using the Movie Studio version of Vegas and Movie Studio is not supported by Mercalli. The reason is that Mercalli uses Vegas Scripting to work around limitations in the Sony plug-in API and Movie Studio doesn’t support the Vegas Pro script API. You will have to use something like Boris FX or Boris RED to stabilize footage with a plug-in. Otherwise use a stand-alone stabilizer.
It would also be helpful in the future if you point out that you are using Movie Studio in your posts. While it is easy enough for us to deduce this now because Vegas Pro 9 doesn’t exist, it will get very confusing in the future when it does exist. There is no such thing as “Vegas 9″… there is Vegas Movie Studio 9 and Vegas Pro 8. Thanks.
~jr
http://www.johnrofrano.com
http://www.vasst.com