Enabling adaptive image style errors

Using drupal 7.12 and 7.1.3 when creating the adaptive image style I get the following error messages.

Image scale failed using the gd toolkit on modules/image/sample.png (image/png, 800x600)

Warning: imagecopyresampled() expects parameter 1 to be resource, boolean given in image_gd_resize() (line 86 of C:\wamp\www\websites\kingfisher\modules\system\image.gd.inc).

Warning: imagesavealpha() expects parameter 1 to be resource, boolean given in image_gd_create_tmp() (line 323 of C:\wamp\www\websites\kingfisher\modules\system\image.gd.inc).

Warning: imagealphablending() expects parameter 1 to be resource, boolean given in image_gd_create_tmp() (line 322 of C:\wamp\www\websites\kingfisher\modules\system\image.gd.inc).

Warning: imagefill() expects parameter 1 to be resource, boolean given in image_gd_create_tmp() (line 321 of C:\wamp\www\websites\kingfisher\modules\system\image.gd.inc).

Warning: imagecolorallocatealpha() expects parameter 1 to be resource, boolean given in image_gd_create_tmp() (line 320 of C:\wamp\www\websites\kingfisher\modules\system\image.gd.inc).

Warning: imagealphablending() expects parameter 1 to be resource, boolean given in image_gd_create_tmp() (line 319 of C:\wamp\www\websites\kingfisher\modules\system\image.gd.inc).

Warning: imagecreatetruecolor() [function.imagecreatetruecolor]: Invalid image dimensions in image_gd_create_tmp() (line 302 of C:\wamp\www\websites\kingfisher\modules\system\image.gd.inc).