Warnings with latest upgrade

Hello,

I am getting these warnings.

warning: imagesx(): supplied argument is not a valid Image resource in /home/content/a/p/p/app1ancomm/html/cms/sites/appiancommercial.com/modules/imageapi/imageapi_gd.module on line 316.
warning: imagesy(): supplied argument is not a valid Image resource in /home/content/a/p/p/app1ancomm/html/cms/sites/appiancommercial.com/modules/imageapi/imageapi_gd.module on line 316.
warning: imagecreatetruecolor() [function.imagecreatetruecolor]: Invalid image dimensions in /home/content/a/p/p/app1ancomm/html/cms/sites/appiancommercial.com/modules/imageapi/imageapi_gd.module on line 317.
warning: imagecreatetruecolor() [function.imagecreatetruecolor]: Invalid image dimensions in /home/content/a/p/p/app1ancomm/html/cms/sites/appiancommercial.com/modules/imageapi/imageapi_gd.module on line 318.
warning: imagecopy(): supplied argument is not a valid Image resource in /home/content/a/p/p/app1ancomm/html/cms/sites/appiancommercial.com/modules/imageapi/imageapi_gd.module on line 334.
warning: imageconvolution() expects parameter 1 to be resource, boolean given in /home/content/a/p/p/app1ancomm/html/cms/sites/appiancommercial.com/modules/imageapi/imageapi_gd.module on line 335.
warning: imagedestroy(): supplied argument is not a valid Image resource in /home/content/a/p/p/app1ancomm/html/cms/sites/appiancommercial.com/modules/imageapi/imageapi_gd.module on line 404.
warning: imagedestroy(): supplied argument is not a valid Image resource in /home/content/a/p/p/app1ancomm/html/cms/sites/appiancommercial.com/modules/imageapi/imageapi_gd.module on line 405.

Drupal 6.10
All modules up-to-date
Using: ImageAPI, ImageCache, ImageField, LightBox2, Views, Contemplate, etc.

Usually occurs once, while a fresh thumbnail is generated by ImageCache, and then the back button is pressed.

Any suggestions would be appreciated.

Regards,
Tigran