You can use the HTML header and footer functions within the style templates to “embed” the UBB.classic™ interface within your existing Web page (using a table):

1. Enter your UBB.classic™ control panel.

2. Click the Styles link.

3. Click Create a New Style Set or choose an existing style from the dropdown and select “edit/copy selected style”.

4. Click the HTML Inserts tab. Insert your Web site’s HTML code into the Header and Footer text boxes, as appropriate. Depending on the content of your HTML, you may need to experiment with how you divide the page.

It is possible to create left and right margins by using header HTML like <table><tr><td>Left Margin</td><td> and footer HTML like </td></tr></table>.

If you have created a new style, remember to go back to each forum and apply the new style to the desired forums.

BTW,
A lot of security holes have been discovered by hackers since the days of classic.
Hence why it is not really supported anymore.

Oh, Okay.
Should be fairly simple if you also downloaded the importer script at the time.
As far as locking yourself out in classic.
You are aware that the member files are in plain text meaning you can access member 1 with a text editor?
It would be like file 00000001.cgi in the member folder.
You can view the file and get all the login info.