I've been following the solidworks api example Batch Update Card Variables Example (C#)

this example is made for files without configurations, but I wanted to try it on solidworks files which do have configurations. Changing the search parameters only to files I personally have checked out (I've been able to do this just fine) and then using SetVar with the string bsConfiguration parameter being "@" does not actually set the variable. Trying to get around this by using (int)EdmBatchFlags.EdmBatch_AllConfigs so that it changes all configs causes the process to fail entirely with the error. 

The interesting thing is I was able to get the @ tab to work once, but I can't figure out how to replicate this behavior. Has anybody gotten a batch update to work before?