Loading all ad files/keyword files raises a timeout error

Haven't seen this before, but is still happening on old builds. May have to do with the added BA's to the keyword/ad taxonomies.

This is the error it raises after attempting to load all the keyword files or all of the ad files:

Timeout sending the file:
perhaps your browser does not send files correctly,
your session has expired,\n or there was a server error.
Please try again.