When I was looking to downgrade, I found that the missing step seemed to be changing the Apache Alias to refer to the older folder.
If you are using a package like say WAMP, the default install folder for the code will be in
root/apps/phpmyadmin3.2.0.1
root/apps/phpmyadmin4.0.4
When you simply type in localhost/phpmyadmin in your browser, Apache will redirect you to whatever the current install is. This is done via an Alias Directory. If you want to revert to an older version, then all you will likely need to do is change the rewrite to point to the older folder.
The file itself probably looks something like:
Alias /phpmyadmin "C:/Server/wamp/apps/phpmyadmin3.4.5/"
#// Make sure these point to the version of the program you want to run.
<Directory "C:/Server/wamp/apps/phpmyadmin3.4.5/">
Options Indexes FollowSymLinks ExecCGI
AllowOverride all
Order Deny,Allow
Deny from all
Allow from 127.0.0.1
Allow from ::1
Allow from localhost
</Directory>