Event Study with estudy2 - Help

Dear R-Studio users,

i try to create a Event study based on the Date 01.06.2018. For that I load the prices from four different companys (tseries package). My problem now is that i want to see the performance of just a single company (e.g VW). The code doesn't run. I want the DAX to operate as a controlgroup in the code. Can't find the problem. Why does it not show me the results of the parametric test with just one company?
Hope you can help me.

used that package: estudy2