The application has crashed with an uncaught exception 'NSInvalidArgumentException'.

For a picker UI on one of my Alloy .xml files :

<Picker id="picker" width="50" height="40" top="50" backgroundColor="transparent"  selectionIndicator="true" useSpinner="true">
    <Column id="column" />
 </Picker>

i tried to add dynamically some rows to the unique column existing in that Picker using a for loop :

for(var i = 0; i < parseInt(parseInt(params.nMaxSp)+1); i++){
 
        Ti.API.error(' FOOOR LOOP i : '+i);
        $.column.addRow(Ti.UI.createPickerRow({title:i}));  
 
 
    }

i got this error :

The application has crashed with an uncaught exception 'NSInvalidArgumentException'.
[ERROR] :  Reason:
[ERROR] :  -[__NSCFNumber length]: unrecognized selector sent to instance 0xe3afdf0
[ERROR] :  Stack trace:
[ERROR] :  0   CoreFoundation                      0x043485c8 __exceptionPreprocess + 152
[ERROR] :  1   libobjc.A.dylib                     0x03e528b6 objc_exception_throw + 44
[ERROR] :  2   CoreFoundation                      0x043e5903 -[NSObject(NSObject) doesNotRecognizeSelector:] + 275
[ERROR] :  3   CoreFoundation                      0x0433890b ___forwarding___ + 1019
[ERROR] :  4   CoreFoundation                      0x043384ee _CF_forwarding_prep_0 + 14
[ERROR] :  5   Foundation                          0x010e78ed -[NSConcreteMutableAttributedString replaceCharactersInRange:withString:] + 39
[ERROR] :  6   Foundation                          0x010e855a -[NSConcreteMutableAttributedString initWithString:attributes:] + 293
[ERROR] :  7   UIKit                               0x01660bc6 -[UILabel _setText:] + 97
[ERROR] :  8   UIKit                               0x01660d84 -[UILabel setText:] + 40
[ERROR] :  9   myAppName                         0x001cad3d -[TiUIPickerRowProxy viewWithFrame:reusingView:] + 701
[ERROR] :  10  myAppName                         0x001c9ee3 -[TiUIPicker pickerView:viewForRow:forComponent:reusingView:] + 451http://www.appcelerator.com/products
[ERROR] :  11  UIKit                               0x014a5aa1 -[UIPickerView tableView:cellForRowAtIndexPath:] + 578
[ERROR] :  12  UIKit                               0x01ae84d4 -[UIPickerColumnView tableView:cellForRowAtIndexPath:] + 59
[ERROR] :  13  UIKit                               0x015a261f -[UITableView _createPreparedCellForGlobalRow:withIndexPath:] + 412
[ERROR] :  14  UIKit                               0x015a26f3 -[UITableView _createPreparedCellForGlobalRow:] + 69
[ERROR] :  15  UIKit                               0x01586774 -[UITableView _updateVisibleCellsNow:] + 2378
[ERROR] :  16  UIKit                               0x01599e95 -[UITableView layoutSubviews] + 213
[ERROR] :  17  UIKit                               0x019d752c -[UIPickerTableView layoutSubviews] + 71
[ERROR] :  18  UIKit                               0x0151e267 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 355
[ERROR] :  19  libobjc.A.dylib                     0x03e6481f -[NSObject performSelector:withObject:] + 70
[ERROR] :  20  QuartzCore                          0x0301f2ea -[CALayer layoutSublayers] + 148
[ERROR] :  21  QuartzCore                          0x030130d4 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 380
[ERROR] :  22  QuartzCore                          0x03012f40 _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 26
[ERROR] :  23  QuartzCore                          0x02f7aae6 _ZN2CA7Context18commit_transactionEPNS_1               0x010e78ed -[NSConcreteMutableAttributedString replaceCharactersInRange:withString:] + 39
....
...
...

i couldn't paste all the error text as i couldn't preview it because it's too long..