[SOLVED] Image Error on uploading thumbnail image

web hosting information:

Gallery version (not just "2"):
PHP version: 5.2.10
PHPInfo Link (see FAQ):
Webserver : apache 2.2.13 (Unix)
Database: MySql 5.0.81
Activated toolkits: ImageMagick, NetPbm, GD (all active)
Operating system : UNIX
Browser : Firefox/3.5.4

I created a new album but failed to upload a JPEG file as thumbnail from my local machine. I got error message as below.

Event Details
Date Mon 02 Nov 2009 12:30:21 PM EST
Type Image Error
Location http://speakphotos.com/gallery/main.php?g2_view=core.ItemAdmin&g2_subView=core.ItemEdit&g2_editPlugin=ItemEditItem&g2_itemId=27
User Id 6
Client 70.31.20.26
Summary Unable to build image
Referer http://speakphotos.com/gallery/main.php
Details

Error (ERROR_TOOLKIT_FAILURE)in modules/jpegtran/classes/JpegtranToolkit.class at line 127 (GalleryCoreApi::error)
in modules/squarethumb/classes/SquareThumbToolkit.class at line 112 (JpegtranToolkit::performOperation)
in modules/core/classes/GalleryDerivative.class at line 452 (SquareThumbToolkit::performOperation)
in modules/core/classes/GalleryDerivative.class at line 274 (GalleryDerivative::_rebuildCache)
in modules/core/classes/GalleryDerivativeImage.class at line 153 (GalleryDerivative::rebuildCache)
in modules/core/classes/helpers/GalleryDerivativeHelper_advanced.class at line 844 (GalleryDerivativeImage::rebuildCache)
in modules/core/classes/GalleryCoreApi.class at line 997 (GalleryDerivativeHelper_advanced::rebuildCache)
in modules/core/classes/helpers/GalleryDerivativeHelper_simple.class at line 50 (GalleryCoreApi::rebuildDerivativeCache)
in modules/core/classes/GalleryCoreApi.class at line 984 (GalleryDerivativeHelper_simple::rebuildCacheIfNotCurrent)
in modules/core/ItemEdit.inc at line 232 (GalleryCoreApi::rebuildDerivativeCacheIfNotCurrent)
in modules/core/ItemAdmin.inc at line 140 (ItemEditView::loadTemplate)
in modules/core/classes/GalleryView.class at line 293 (ItemAdminView::loadTemplate)
in main.php at line 465 (GalleryView::doLoadTemplate)
in main.php at line 104
in main.php at line 88

Request variables: Array
(
[view] => core.ItemAdmin
[subView] => core.ItemEdit
[editPlugin] => ItemEditItem
[itemId] => 27
)

It works. Thanks a lot!