Error when adding text

I recently re-installed Imagecache Actions and attempted to add text to an existing Imagecache preset. I had previously installed Imagecache Actions, but uninstalled after deciding that it was of no use to me then (I don't know if this is part of the issue or not, but I figured it doesn't hurt to mention). When I updated the preset with the new text action added, I got the following error messages:

* warning: imagecolorallocatealpha(): supplied argument is not a valid Image resource in [path]\modules\imagecache_actions\textactions.inc on line 455.
* warning: imagesavealpha(): supplied argument is not a valid Image resource in [path]\modules\imagecache_actions\textactions.inc on line 460.
* warning: imagealphablending(): supplied argument is not a valid Image resource in [path]\modules\imagecache_actions\textactions.inc on line 461.
* warning: imagettftext() expects parameter 1 to be resource, null given in [path]\modules\imagecache_actions\textactions.inc on line 463.

Now the image doesn't show up, and I get this error message on every Drupal page - even ones that the preset do not show up on. If I delete the text action, it works fine again. Am I doing something wrong, or is this a bug? I can provide additional information as needed.

Thanks!