calling function with String resolves as "Unknown" instead of varchar

I'm calling a function with the following signature:

create or replace function
usp_affectedproduct(integer, integer, varchar) RETURNS
int as ...

I'm calling the function with something similar to:

String query = "{? = call usp_affectedproducts(?, ?,
?)}";
Connection conn = null;                CallableStatement s = null;
try {
  conn = getConnection(datasource);
  s = conn.prepareCall(query);
  s.registerOutParameter(1,Types.INTEGER);
  s.setInt(2,qualityid);
  s.setInt(3,submitid);
  s.setString(4,products[x].getName());
  s.execute();
  } catch (SQLException e) {
   throw e;
  }finally{
     <clean up stuff ...>

When I run this, I get an SQLException stating:

function usp_affectedproducts(integer, integer,
"unknown") does not exist

I've also try s.setObject(4, aString, Types.VARCHAR),
also to no avail.  I've tried using a
PreparedStatement instead of the CallableStatement -
again, without success.

Any ideas?  I'm running 7.4.1 on RedHat 8.0 with JDK
1.4.1_01.

Thanks in advance



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