[support] Problems Rebuilding Content Permissions

[Andy Theuninck]

Drupal (6.20) recently prompted me to rebuild content access
permissions. This occurred after installing the Taxonomy Access
Control Lite module.

When I follow the provided link, there's a prompt warning that
rebuilding permissions may take a while with yes/no option to
continue. Confirming the rebuild goes to
{drupal_installation}/batch?op=start&id=28. This screen shows a bar
that says "Initializing". This screen stays like that forever with no
sign of progress nor any error messages (at this point, I'm reasonably
comfortable calling 72+ hours "forever").

It seems extremely likely to me that this rebuilding process is not
working. As such:

1. Is there any alternate way that I can rebuild permissions?
2. Is there any way that I can turn on more verbose output to figure
out what's going wrong?
3. Anything else I can check (.htaccess/host issues, configuration
settings, etc)?

If it's relevant, I have currently ~50 content nodes and 6 roles.