Index Error on opening DBF IV tables

Hy everyone !

I am trying to open a DBase IV Table using TDatabase, TQuery, TDataSource
and TDBGrid. If I set the Query (Table is the same) active in the VCL I can
see the Data in the grid.
Opening it at runtime it tells me "Index missing or corrupt".
The same Errormessage shows DBD32 and DBEXPLORE.
The DBF-File has also an MDX in the same Directory.

I'm using D5 C/S, BDE 5.01.

Someone has an idea ?

thanks

Klaus Kuhl