Dortego,
I believe the issue is with the job tags above. In the current setting (with all the *s) you are telling the service to run the method, at some point, any minute of any hour of any day of any month. As you mention this is a nightly job, I would suggest setting the hours to 23, 0, or 01 (and the minutes to something like 02 to account for any timing issues). [For testing, just choose the current hour and put the minutes in the next 5 or 10, so if it's 9:30 AM, set the test at 9 hours 35 minutes.] Also, with the current setting, this method will run every day; if you want it to run only on standard business days, you should probably set days to 1,2,3,4,5 as 0 and 6 represent Sunday and Saturday, respectively (all the time-type values can be a comma-separated list, see the blog post for more information).
Let me know if that works,
Sam