What does this error mean when running ksvm of kernlab package in R

I am calling the ksvm method for the kernlab package in R using the following syntax

svmFit = ksvm(x=solTrainXtrans, y=solTrainYSVM, kernel="stringdot", kpar="automatic", C=1, epsilon=0.1)

      

        
        
        
      

    

The x parameter is a data.frame with the attributes of the function, and the y parameter is a list with different values.

The following error appears when running the specified line.

Error in do.call(kernel, kpar) : second argument must be a list

      

        
        
        
      

    

What is he trying to tell me here?