@Jack_Ventura We need a good deal more information before anyone could hazard a guess as to what this problem is.
When you say "data from year 1998", does that mean you have data in an older mdb created back in 1998? Or something else?
If we are talking about an old mdb, which was created by the 1997 version of Access, then that would be a known issue. You'll need to convert it from the 1997 version to a newer one using an intermediate version of Access, probably 2003. If that's not the case, as noted, more information would be necessary.