Recovering version 4.0 database

[Derek McKinnon]

I occasionally need some data out of some old databases. We have a copy of all the .frm files, and are pretty sure it they were last run in version 4.0. I currently run 5.1.

I tried simply creating a new database, shutting down the service (I'm in windows), copying the files across and starting the service, but when running a simply select query it fails.

eg. Select * from dr01
Error is "Table 'swt.dr01' doesn't exist.

Using "REPAIR TABLE dr01" gives a return of
"Table swt.dr01' doesn't exist.

Using "REPAIR TABLE dr01 USE_FRM" gives
"Failed repairing incompatible .frm file.

So I'm guessing that MySQL 5.1 can't open files from 4.0. What's the easiest way to upgrade the files so we can access them?