void closeDBFfile();

When you finish working with a DBF file you have to close it.

{
    CDBFapi dbf = new CDBFapi();
    if (!dbf || !dbf.libraryLoaded()) return;

    if (dbf.openDBFfile("c:\\tmp\\example.dbf"))
    {
        // your code
        dbf.closeDBFFile();
    }
    dbf = nil;
}