Warnings for Cell Array Arguments to oct-file

[Robert Wilkerson]

I have built a .oct file/function which allows the caller to pass in 
arguments which are cell arrays of character strings like so:

Result = ReadAndProcess(...
  {'A1.xml', 'A2.xml'},...
  {'B1.xml'},...
  {'C1.xml', 'C2.xml', 'C3.xml'});

My code compiles without error and produces the correct output when 
executed.  However, during execution I'm getting a bunch of the 
following warning messages:

warning: implicit conversion from matrix to sq_string

...with a line number that points to the above call as the problem.

Is there something incompatible about the syntax I am using for this 
call?  I can't seem to find much online when searching for this warning 
message.

Thanks in advance,
Robert