Cell reference is out of range - But I use GetDataRange() - google-apps-script

Question

I've tried a bunch of solution but it always end with Cell ref is out of range.
I thought that GetDataRange() & GetLastRow() would cover the last non-blank cell but I'm stuck. I've tried to hardcode my cell values (from X to Y) but nothing seems to change.
var course;
var searchingCol;
function CalculateFurnitureList()
{
GetCourseString();
FindColumnNumber(course);
GetSpecialFurnituresValue();
}
function GetCourseString()
{
var activeSheet = SpreadsheetApp.getActiveSheet();
var courseType = activeSheet.getRange("A2").getValue();
Browser.msgBox('Generate furniture list for ' + courseType + ' course');
course = courseType;
}
function FindColumnNumber(ct)
{
var furnitureSheet = SpreadsheetApp.getActive().getSheetByName("MaterielCours");
var range = furnitureSheet.getDataRange();
var width = range.getWidth();
//Search every cell in the designated area to find the course name
for (var i = 1; i <= width; i++)
{
var data = range.getCell(1,i);
if (data.getValue() == ct)
{
Browser.msgBox('Trouvé ! ' + data.getValue() + ' se trouve en : ' + i +':1');
searchingCol = i;
}
}
}
function GetSpecialFurnituresValue()
{
Browser.msgBox(searchingCol);
var furnitureSheet = SpreadsheetApp.getActive().getSheetByName("MaterielCours");
var range = furnitureSheet.getDataRange();
var length = range.getLastRow();
for (var i = 1; i < length; i++)
{
var data = range.getCell(searchingCol, i);
if (data.getValue() !== "")
{
// Do nothing
}
else
{
if (data == "Abs")
{
Browser.msgBox('NTM');
}
else
{
// Calculate value
}
}
}
}
It's
var data = range.getCell(searchingCol, i);
in GetSpecialFurnituresValue() which causes the problem.
The weird thing is that the same process in FindColumnNumber is working perfectly.

Answer 1

(editing my original answer - I must have been tired!) In the function GetSpecialFurnitureValues, there are a few things.
The for loop uses i < length, but it should be <= or you will miss the last row:
// for (var i = 1; i < length; i++)
for (var i = 1; i <= length; i++)
Your column/rows were simply reversed. :)
// var data = range.getCell(searchingCol, i);
var data = range.getCell(i, searchingCol);
Hope that helps!