iDB2ConversionException on ExecuteNonQuery() only on Server

I have a strange error I am trying to figure out. I am getting
a DB2ConversionException on an ExecuteNonQuery(). I am running a stored
procedure that calls an RPG program. This works perfect on my own PC.
However, when I publish it to the web server, I get the error.

public void SignTimeSheet(Timesheet timesheet, string approved)
{
// Get the data from the iSeries
using (iDB2Connection conn = new iDB2Connection(_CONNSTRING))
{
conn.Open();

iDB2Command cmd = conn.CreateCommand();
cmd.CommandType = CommandType.StoredProcedure;

if ((String.IsNullOrEmpty(timesheet.SupervisorComments)) &&
(approved == " "))
{
cmd.CommandText = "MPRLIB.APPROVETIMESHEET";

cmd.Parameters.Add("@SSN",
timesheet.EmployeeUniqueKey.ToString("0000000000"));
cmd.Parameters.Add("@PAPER",
timesheet.EmployeeSignedPaper);
cmd.Parameters.Add("@SUPERVISORID",
timesheet.SupervisorUserId);
cmd.Parameters.Add("@SIGNEDUSER",
timesheet.SupervisorSignedBy);
cmd.Parameters.Add("@WORKSTATION",
timesheet.SupervisorSignedComputer);
}
else
{
cmd.CommandText = "MPRLIB.APPROVETIMESHEETWCOMMENT";

cmd.Parameters.Add("@SSN",
timesheet.EmployeeUniqueKey.ToString("0000000000"));
cmd.Parameters.Add("@PAPER",
timesheet.EmployeeSignedPaper);
cmd.Parameters.Add("@APPROVE", approved);
cmd.Parameters.Add("@SIGNEDUSER",
timesheet.SupervisorSignedBy);
cmd.Parameters.Add("@WORKSTATION",
timesheet.SupervisorSignedComputer);
cmd.Parameters.Add("@COMMENT",
timesheet.SupervisorComments);
}

cmd.ExecuteNonQuery();
conn.Close();
}
}

Any ideas on what it might be or how to debug this on the server?

--
Mike Wills
http://mikewills.info