What is a ADT file?

[Mustard]

I run vista, and i was trying to edit one of my zips for a add on, and it said "CONVERT TO ADT FILE"
                                                                                                                          C:/error 3542
What does this mean?

[Ad Bot]

[Mustard]

Bump

[Space Guy]

I searched Google for 'adt filetype'. This was the first result.

http://filext.com/file-extension/ADT

Do you have any of the listed programs? (e.g. AdTech Fax, Advantage Database Server)

[Mustard]

Thanks Space, i got it.
I got tuneup and deleted the extension.