1) Under your BBW directory (bbw100), create a directory called 'U-1998.wdd'. (mkdir u-1998.wdd)
2) Change to that newly created directory. (cd u-1998.wdd)
3) Create another directory called 'org00001'. (mkdir org00001)
4) Change to that directory. (cd org00001)
5) Unzip the file called org97.zip in the org00001 directory. (pkunzip org97.zip .)
5) Change directory to the 'U-1998.wdd'. (cd ..)
6) Unzip the file called data97.zip in the 'U-1998.wdd' directory. (pkunzip data97.zip)
Update: The above instructions caused some problems. Here's the fix. What happens is if you create a directory u-1998 and a sub-directory org00001 and then unzip the files they do not show up in BBW because it does not see it because it is not in the INI file.
The easiest way to do this is Start Advanced draft and then select create a data disk. Name it what you said (u-1998) it will add the wdd. Then select 'add organization', name it anything you want THEN unzip the files you made into the corresponding Directorys then it will show up.