Tinymce confused with image.assist module

With Drupal 4.6/CVS and the latest CVS modules, I am experiencing an error when using the tinymce.module in combination with image_assist.

I've set the tinymce theme to "advanced," since this seems to integrate the two modules automatically (according to the "readme" in the tinymce durpalimage plugin directory). This plugin seems to be installed correctly, as Tinymce finds the plugin and tries to use it (initially the tinymce setup page gave me an error that the plugin was not accessible-- I hadn't loaded it to the right place-- now this seems to be right).

However, using imageassist (from the image button in tinymce) creates this error:

getimagesize(): Read error! in /home/WWW/drupal/modules/img_assist/img_assist.module on line 521.

The imageassist window opens, but several of the thumbnails are broken in this window. The above error message is generated within the same window. If I try to add images, the image mdoules browse window opens and I can browse and select an image. But when I "submit" a new image for upload, the browser informs me that

"the browser window has lost communication with the parent form, so images can no longer be inserted. This problem is usually solved by reopening this window from the originating link. Would you like to close this browser now?"

Despite all of this, the image module does upload the image. However, the image_assist.module is rendered mostly inoperable at this point. While I can preview a snippet, the insert image button does nothing. These problems only result when trying to run both modules together, as the image_assist module works perfectly on its own (I'll also submit this bug report to the image_assist project, as I'm not sure its a problem with the tinymce plugin or the way image_assist is interracting with it).

Thank you for your help in resolving these issues!