Edit User Defaults Error

After clicking on the Edit New User Defaults button and submitting the form on the next page, I receive the following error:

Error - Missing Content-Type Header

The form changes are saved, so the error doesn't seem to be causing any real problems. I also see a similar error in miniserv.error:

/virtual-server/save_defaults.cgi :
Missing Content-Type Header

Status: 
Closed (fixed)