I'm not sure how Cyrilbiker expects your file to open if you've no longer got Publisher 98 on your computer!
All Microsoft products are meant to be 'backwards compatible'. The fact that they've programmed an error message into P2000 saying it can't open a file from an earlier edition seems to show that they know that their products aren't always backwards compatible!!!
Normally, you should be able to open a P98 file in P2000 (even though you might have to tweak a bit of the design after opening). It looks as if there might be a quirk in the way the document was saved. (I've just spent half an hour on Microsoft's website. It seems determined to refuse to accept that your problem exists!).
All I can suggest, I'm afraid, is finding someone who's got a different version of Publisher (e.g. 2002) and seeing if they can open the file. If so, they can use 'save as' to save a copy in P2000 format for you. (If the document's not confidential, you could e-mail it to me and I'd try this for you. If you want to do this, use the (only) e-mail address at www.webtribe.net/~yewlandspast).
Chris