"Import OS Files": Error occured while uploading the files.

8.0 HF1

When I try to upload the sources folder for an OS, the Web console returns "Error occured while uploading the files."

The Altiris log shows this:

Exception of type 'System.Web.HttpUnhandledException' was thrown.

HTTP Request failed:
 /Altiris/Deployment/OSSourceFilesConfigurationEditor.aspx?&method=addManifest&guid=&controlId=osFileBrowse

Validation of Anti-XSRF token failed. Accessing page: https://deploy.dept.example.edu/Altiris/Deployment...

Thoughts?

Thanks!