Workflow C# string function error in Docusign - docusignapi

Question

I have an code issue in docusign.
In my calculation step I have created and input and output code.
When I run the template and checking the "incoming data" xml in the workflow I have an error message displayed:
<In_80_stackTrace>Exception: at ADEXS.DynamicCode.DynamicClassD_3447d8ccd49f4631b91c31df53e249e7.DynamicMethodD_dcb572b7876d400683579290c5918f06(DynamicContext _context)</In_80_stackTrace>
I don't know how to fix this that it will show only the
logError("In_80_error", "Data node //CategoryName is missing");
when no data is in the node.
Below are the details - my input code:
//In_80 - ESP_CategoryName_Description
string In_80 = "";
{
try
{
if (incomingDataRoot.SelectSingleNode("//CategoryName[node()]").InnerText == null)
{
logError("In_80_error", "Data node //CategoryName is missing");
}
else if (incomingDataRoot.SelectSingleNode("//CategoryName[node()]").InnerText != null)
{
In_80 = incomingDataRoot.SelectSingleNode("//CategoryName[node()]").InnerText;
}
}
catch (Exception e)
{
//logError("In_80_error", "Exception: Message:" + e.Message +" Inner Exception: "+ e.InnerException +" StackTrace: "+ e.StackTrace +" Source: "+ e.Source +" Data: "+ e.Data);
logError("In_80_stackTrace", "Exception: " + e.StackTrace);
}
}
Here is the output code:
//OUT_92 - ESP_CategoryName_Description
var OUT_92 = In_80;
if (In_80 == "")
{
logError("OUT_92_error", "Error reading In_80");
} else {
XmlElement elem = incomingDataRoot.OwnerDocument.CreateElement("OUT_92");
string p_category = "";
int i = 1;
foreach (char item in In_80)
{
if (Char.IsLetter(item))
{
if (i == 1)
{
p_category += item.ToString().ToUpper();
}
else
{
p_category += item.ToString().ToLower();
}
i++;
}
else
{
if (item == ' ')
{
i = 1;
}
p_category += item.ToString();
}
}
OUT_92 = p_category;
elem.InnerText = OUT_92.ToString();
elem.SetAttribute("Name", "ESP_CategoryName_Description");
incomingDataRoot.SelectSingleNode("/Root/Params/TemplateFieldData/Calculation_Results").AppendChild(elem);
}
In incoming data OUT part I'm getting
<OUT_92_error>Error reading In_80</OUT_92_error>
where I assume that its because something is wrong with the input code part?
Thank you for your help!